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src/qt/src/3rdparty/sqlite/sqliteInt.h
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00001 /*
00002 ** 2001 September 15
00003 **
00004 ** The author disclaims copyright to this source code.  In place of
00005 ** a legal notice, here is a blessing:
00006 **
00007 **    May you do good and not evil.
00008 **    May you find forgiveness for yourself and forgive others.
00009 **    May you share freely, never taking more than you give.
00010 **
00011 *************************************************************************
00012 ** Internal interface definitions for SQLite.
00013 **
00014 ** @(#) $Id: qt/sqliteInt.h   3.3.8   edited Mar 30 2004 $
00015 */
00016 #include "config.h"
00017 #include "sqlite.h"
00018 #include "hash.h"
00019 #include "parse.h"
00020 #include "btree.h"
00021 #include <stdio.h>
00022 #include <stdlib.h>
00023 #include <string.h>
00024 #include <assert.h>
00025 
00026 /*
00027 ** The maximum number of in-memory pages to use for the main database
00028 ** table and for temporary tables.
00029 */
00030 #define MAX_PAGES   2000
00031 #define TEMP_PAGES   500
00032 
00033 /*
00034 ** If the following macro is set to 1, then NULL values are considered
00035 ** distinct for the SELECT DISTINCT statement and for UNION or EXCEPT
00036 ** compound queries.  No other SQL database engine (among those tested) 
00037 ** works this way except for OCELOT.  But the SQL92 spec implies that
00038 ** this is how things should work.
00039 **
00040 ** If the following macro is set to 0, then NULLs are indistinct for
00041 ** SELECT DISTINCT and for UNION.
00042 */
00043 #define NULL_ALWAYS_DISTINCT 0
00044 
00045 /*
00046 ** If the following macro is set to 1, then NULL values are considered
00047 ** distinct when determining whether or not two entries are the same
00048 ** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
00049 ** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
00050 ** is the way things are suppose to work.
00051 **
00052 ** If the following macro is set to 0, the NULLs are indistinct for
00053 ** a UNIQUE index.  In this mode, you can only have a single NULL entry
00054 ** for a column declared UNIQUE.  This is the way Informix and SQL Server
00055 ** work.
00056 */
00057 #define NULL_DISTINCT_FOR_UNIQUE 1
00058 
00059 /*
00060 ** The maximum number of attached databases.  This must be at least 2
00061 ** in order to support the main database file (0) and the file used to
00062 ** hold temporary tables (1).  And it must be less than 256 because
00063 ** an unsigned character is used to stored the database index.
00064 */
00065 #define MAX_ATTACHED 10
00066 
00067 /*
00068 ** The next macro is used to determine where TEMP tables and indices
00069 ** are stored.  Possible values:
00070 **
00071 **   0    Always use a temporary files
00072 **   1    Use a file unless overridden by "PRAGMA temp_store"
00073 **   2    Use memory unless overridden by "PRAGMA temp_store"
00074 **   3    Always use memory
00075 */
00076 #ifndef TEMP_STORE
00077 # define TEMP_STORE 1
00078 #endif
00079 
00080 /*
00081 ** When building SQLite for embedded systems where memory is scarce,
00082 ** you can define one or more of the following macros to omit extra
00083 ** features of the library and thus keep the size of the library to
00084 ** a minimum.
00085 */
00086 /* #define SQLITE_OMIT_AUTHORIZATION  1 */
00087 /* #define SQLITE_OMIT_INMEMORYDB     1 */
00088 /* #define SQLITE_OMIT_VACUUM         1 */
00089 /* #define SQLITE_OMIT_DATETIME_FUNCS 1 */
00090 /* #define SQLITE_OMIT_PROGRESS_CALLBACK 1 */
00091 
00092 /*
00093 ** Integers of known sizes.  These typedefs might change for architectures
00094 ** where the sizes very.  Preprocessor macros are available so that the
00095 ** types can be conveniently redefined at compile-type.  Like this:
00096 **
00097 **         cc '-DUINTPTR_TYPE=long long int' ...
00098 */
00099 #ifndef UINT32_TYPE
00100 # define UINT32_TYPE unsigned int
00101 #endif
00102 #ifndef UINT16_TYPE
00103 # define UINT16_TYPE unsigned short int
00104 #endif
00105 #ifndef UINT8_TYPE
00106 # define UINT8_TYPE unsigned char
00107 #endif
00108 #ifndef INT8_TYPE
00109 # define INT8_TYPE signed char
00110 #endif
00111 #ifndef INTPTR_TYPE
00112 # if SQLITE_PTR_SZ==4
00113 #   define INTPTR_TYPE int
00114 # else
00115 #   define INTPTR_TYPE long long
00116 # endif
00117 #endif
00118 typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
00119 typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
00120 typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
00121 typedef UINT8_TYPE i8;             /* 1-byte signed integer */
00122 typedef INTPTR_TYPE ptr;           /* Big enough to hold a pointer */
00123 typedef unsigned INTPTR_TYPE uptr; /* Big enough to hold a pointer */
00124 
00125 /*
00126 ** Defer sourcing vdbe.h until after the "u8" typedef is defined.
00127 */
00128 #include "vdbe.h"
00129 
00130 /*
00131 ** Most C compilers these days recognize "long double", don't they?
00132 ** Just in case we encounter one that does not, we will create a macro
00133 ** for long double so that it can be easily changed to just "double".
00134 */
00135 #ifndef LONGDOUBLE_TYPE
00136 # define LONGDOUBLE_TYPE long double
00137 #endif
00138 
00139 /*
00140 ** This macro casts a pointer to an integer.  Useful for doing
00141 ** pointer arithmetic.
00142 */
00143 #define Addr(X)  ((uptr)X)
00144 
00145 /*
00146 ** The maximum number of bytes of data that can be put into a single
00147 ** row of a single table.  The upper bound on this limit is 16777215
00148 ** bytes (or 16MB-1).  We have arbitrarily set the limit to just 1MB
00149 ** here because the overflow page chain is inefficient for really big
00150 ** records and we want to discourage people from thinking that 
00151 ** multi-megabyte records are OK.  If your needs are different, you can
00152 ** change this define and recompile to increase or decrease the record
00153 ** size.
00154 **
00155 ** The 16777198 is computed as follows:  238 bytes of payload on the
00156 ** original pages plus 16448 overflow pages each holding 1020 bytes of
00157 ** data.
00158 */
00159 #define MAX_BYTES_PER_ROW  1048576
00160 /* #define MAX_BYTES_PER_ROW 16777198 */
00161 
00162 /*
00163 ** If memory allocation problems are found, recompile with
00164 **
00165 **      -DMEMORY_DEBUG=1
00166 **
00167 ** to enable some sanity checking on malloc() and free().  To
00168 ** check for memory leaks, recompile with
00169 **
00170 **      -DMEMORY_DEBUG=2
00171 **
00172 ** and a line of text will be written to standard error for
00173 ** each malloc() and free().  This output can be analyzed
00174 ** by an AWK script to determine if there are any leaks.
00175 */
00176 #ifdef MEMORY_DEBUG
00177 # define sqliteMalloc(X)    sqliteMalloc_(X,1,__FILE__,__LINE__)
00178 # define sqliteMallocRaw(X) sqliteMalloc_(X,0,__FILE__,__LINE__)
00179 # define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
00180 # define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
00181 # define sqliteStrDup(X)    sqliteStrDup_(X,__FILE__,__LINE__)
00182 # define sqliteStrNDup(X,Y) sqliteStrNDup_(X,Y,__FILE__,__LINE__)
00183   void sqliteStrRealloc(char**);
00184 #else
00185 # define sqliteRealloc_(X,Y) sqliteRealloc(X,Y)
00186 # define sqliteStrRealloc(X)
00187 #endif
00188 
00189 /*
00190 ** This variable gets set if malloc() ever fails.  After it gets set,
00191 ** the SQLite library shuts down permanently.
00192 */
00193 extern int sqlite_malloc_failed;
00194 
00195 /*
00196 ** The following global variables are used for testing and debugging
00197 ** only.  They only work if MEMORY_DEBUG is defined.
00198 */
00199 #ifdef MEMORY_DEBUG
00200 extern int sqlite_nMalloc;       /* Number of sqliteMalloc() calls */
00201 extern int sqlite_nFree;         /* Number of sqliteFree() calls */
00202 extern int sqlite_iMallocFail;   /* Fail sqliteMalloc() after this many calls */
00203 #endif
00204 
00205 /*
00206 ** Name of the master database table.  The master database table
00207 ** is a special table that holds the names and attributes of all
00208 ** user tables and indices.
00209 */
00210 #define MASTER_NAME       "sqlite_master"
00211 #define TEMP_MASTER_NAME  "sqlite_temp_master"
00212 
00213 /*
00214 ** The name of the schema table.
00215 */
00216 #define SCHEMA_TABLE(x)  (x?TEMP_MASTER_NAME:MASTER_NAME)
00217 
00218 /*
00219 ** A convenience macro that returns the number of elements in
00220 ** an array.
00221 */
00222 #define ArraySize(X)    (sizeof(X)/sizeof(X[0]))
00223 
00224 /*
00225 ** Forward references to structures
00226 */
00227 typedef struct Column Column;
00228 typedef struct Table Table;
00229 typedef struct Index Index;
00230 typedef struct Instruction Instruction;
00231 typedef struct Expr Expr;
00232 typedef struct ExprList ExprList;
00233 typedef struct Parse Parse;
00234 typedef struct Token Token;
00235 typedef struct IdList IdList;
00236 typedef struct SrcList SrcList;
00237 typedef struct WhereInfo WhereInfo;
00238 typedef struct WhereLevel WhereLevel;
00239 typedef struct Select Select;
00240 typedef struct AggExpr AggExpr;
00241 typedef struct FuncDef FuncDef;
00242 typedef struct Trigger Trigger;
00243 typedef struct TriggerStep TriggerStep;
00244 typedef struct TriggerStack TriggerStack;
00245 typedef struct FKey FKey;
00246 typedef struct Db Db;
00247 typedef struct AuthContext AuthContext;
00248 
00249 /*
00250 ** Each database file to be accessed by the system is an instance
00251 ** of the following structure.  There are normally two of these structures
00252 ** in the sqlite.aDb[] array.  aDb[0] is the main database file and
00253 ** aDb[1] is the database file used to hold temporary tables.  Additional
00254 ** databases may be attached.
00255 */
00256 struct Db {
00257   char *zName;         /* Name of this database */
00258   Btree *pBt;          /* The B*Tree structure for this database file */
00259   int schema_cookie;   /* Database schema version number for this file */
00260   Hash tblHash;        /* All tables indexed by name */
00261   Hash idxHash;        /* All (named) indices indexed by name */
00262   Hash trigHash;       /* All triggers indexed by name */
00263   Hash aFKey;          /* Foreign keys indexed by to-table */
00264   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
00265   u16 flags;           /* Flags associated with this database */
00266   void *pAux;          /* Auxiliary data.  Usually NULL */
00267   void (*xFreeAux)(void*);  /* Routine to free pAux */
00268 };
00269 
00270 /*
00271 ** These macros can be used to test, set, or clear bits in the 
00272 ** Db.flags field.
00273 */
00274 #define DbHasProperty(D,I,P)     (((D)->aDb[I].flags&(P))==(P))
00275 #define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].flags&(P))!=0)
00276 #define DbSetProperty(D,I,P)     (D)->aDb[I].flags|=(P)
00277 #define DbClearProperty(D,I,P)   (D)->aDb[I].flags&=~(P)
00278 
00279 /*
00280 ** Allowed values for the DB.flags field.
00281 **
00282 ** The DB_Locked flag is set when the first OP_Transaction or OP_Checkpoint
00283 ** opcode is emitted for a database.  This prevents multiple occurances
00284 ** of those opcodes for the same database in the same program.  Similarly,
00285 ** the DB_Cookie flag is set when the OP_VerifyCookie opcode is emitted,
00286 ** and prevents duplicate OP_VerifyCookies from taking up space and slowing
00287 ** down execution.
00288 **
00289 ** The DB_SchemaLoaded flag is set after the database schema has been
00290 ** read into internal hash tables.
00291 **
00292 ** DB_UnresetViews means that one or more views have column names that
00293 ** have been filled out.  If the schema changes, these column names might
00294 ** changes and so the view will need to be reset.
00295 */
00296 #define DB_Locked          0x0001  /* OP_Transaction opcode has been emitted */
00297 #define DB_Cookie          0x0002  /* OP_VerifyCookie opcode has been emiited */
00298 #define DB_SchemaLoaded    0x0004  /* The schema has been loaded */
00299 #define DB_UnresetViews    0x0008  /* Some views have defined column names */
00300 
00301 
00302 /*
00303 ** Each database is an instance of the following structure.
00304 **
00305 ** The sqlite.file_format is initialized by the database file
00306 ** and helps determines how the data in the database file is
00307 ** represented.  This field allows newer versions of the library
00308 ** to read and write older databases.  The various file formats
00309 ** are as follows:
00310 **
00311 **     file_format==1    Version 2.1.0.
00312 **     file_format==2    Version 2.2.0. Add support for INTEGER PRIMARY KEY.
00313 **     file_format==3    Version 2.6.0. Fix empty-string index bug.
00314 **     file_format==4    Version 2.7.0. Add support for separate numeric and
00315 **                       text datatypes.
00316 **
00317 ** The sqlite.temp_store determines where temporary database files
00318 ** are stored.  If 1, then a file is created to hold those tables.  If
00319 ** 2, then they are held in memory.  0 means use the default value in
00320 ** the TEMP_STORE macro.
00321 **
00322 ** The sqlite.lastRowid records the last insert rowid generated by an
00323 ** insert statement.  Inserts on views do not affect its value.  Each
00324 ** trigger has its own context, so that lastRowid can be updated inside
00325 ** triggers as usual.  The previous value will be restored once the trigger
00326 ** exits.  Upon entering a before or instead of trigger, lastRowid is no
00327 ** longer (since after version 2.8.12) reset to -1.
00328 **
00329 ** The sqlite.nChange does not count changes within triggers and keeps no
00330 ** context.  It is reset at start of sqlite_exec.
00331 ** The sqlite.lsChange represents the number of changes made by the last
00332 ** insert, update, or delete statement.  It remains constant throughout the
00333 ** length of a statement and is then updated by OP_SetCounts.  It keeps a
00334 ** context stack just like lastRowid so that the count of changes
00335 ** within a trigger is not seen outside the trigger.  Changes to views do not
00336 ** affect the value of lsChange.
00337 ** The sqlite.csChange keeps track of the number of current changes (since
00338 ** the last statement) and is used to update sqlite_lsChange.
00339 */
00340 struct sqlite {
00341   int nDb;                      /* Number of backends currently in use */
00342   Db *aDb;                      /* All backends */
00343   Db aDbStatic[2];              /* Static space for the 2 default backends */
00344   int flags;                    /* Miscellanous flags. See below */
00345   u8 file_format;               /* What file format version is this database? */
00346   u8 safety_level;              /* How aggressive at synching data to disk */
00347   u8 want_to_close;             /* Close after all VDBEs are deallocated */
00348   u8 temp_store;                /* 1=file, 2=memory, 0=compile-time default */
00349   u8 onError;                   /* Default conflict algorithm */
00350   int next_cookie;              /* Next value of aDb[0].schema_cookie */
00351   int cache_size;               /* Number of pages to use in the cache */
00352   int nTable;                   /* Number of tables in the database */
00353   void *pBusyArg;               /* 1st Argument to the busy callback */
00354   int (*xBusyCallback)(void *,const char*,int);  /* The busy callback */
00355   void *pCommitArg;             /* Argument to xCommitCallback() */   
00356   int (*xCommitCallback)(void*);/* Invoked at every commit. */
00357   Hash aFunc;                   /* All functions that can be in SQL exprs */
00358   int lastRowid;                /* ROWID of most recent insert (see above) */
00359   int priorNewRowid;            /* Last randomly generated ROWID */
00360   int magic;                    /* Magic number for detect library misuse */
00361   int nChange;                  /* Number of rows changed (see above) */
00362   int lsChange;                 /* Last statement change count (see above) */
00363   int csChange;                 /* Current statement change count (see above) */
00364   struct sqliteInitInfo {       /* Information used during initialization */
00365     int iDb;                       /* When back is being initialized */
00366     int newTnum;                   /* Rootpage of table being initialized */
00367     u8 busy;                       /* TRUE if currently initializing */
00368   } init;
00369   struct Vdbe *pVdbe;           /* List of active virtual machines */
00370   void (*xTrace)(void*,const char*);     /* Trace function */
00371   void *pTraceArg;                       /* Argument to the trace function */
00372 #ifndef SQLITE_OMIT_AUTHORIZATION
00373   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
00374                                 /* Access authorization function */
00375   void *pAuthArg;               /* 1st argument to the access auth function */
00376 #endif
00377 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
00378   int (*xProgress)(void *);     /* The progress callback */
00379   void *pProgressArg;           /* Argument to the progress callback */
00380   int nProgressOps;             /* Number of opcodes for progress callback */
00381 #endif
00382 };
00383 
00384 /*
00385 ** Possible values for the sqlite.flags and or Db.flags fields.
00386 **
00387 ** On sqlite.flags, the SQLITE_InTrans value means that we have
00388 ** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement
00389 ** transaction is active on that particular database file.
00390 */
00391 #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
00392 #define SQLITE_Initialized    0x00000002  /* True after initialization */
00393 #define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
00394 #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
00395 #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
00396 #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
00397 #define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
00398 #define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
00399                                           /*   DELETE, or UPDATE and return */
00400                                           /*   the count using a callback. */
00401 #define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
00402                                           /*   result set is empty */
00403 #define SQLITE_ReportTypes    0x00000200  /* Include information on datatypes */
00404                                           /*   in 4th argument of callback */
00405 
00406 /*
00407 ** Possible values for the sqlite.magic field.
00408 ** The numbers are obtained at random and have no special meaning, other
00409 ** than being distinct from one another.
00410 */
00411 #define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
00412 #define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
00413 #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
00414 #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
00415 
00416 /*
00417 ** Each SQL function is defined by an instance of the following
00418 ** structure.  A pointer to this structure is stored in the sqlite.aFunc
00419 ** hash table.  When multiple functions have the same name, the hash table
00420 ** points to a linked list of these structures.
00421 */
00422 struct FuncDef {
00423   void (*xFunc)(sqlite_func*,int,const char**);  /* Regular function */
00424   void (*xStep)(sqlite_func*,int,const char**);  /* Aggregate function step */
00425   void (*xFinalize)(sqlite_func*);           /* Aggregate function finializer */
00426   signed char nArg;         /* Number of arguments.  -1 means unlimited */
00427   signed char dataType;     /* Arg that determines datatype.  -1=NUMERIC, */
00428                             /* -2=TEXT. -3=SQLITE_ARGS */
00429   u8 includeTypes;          /* Add datatypes to args of xFunc and xStep */
00430   void *pUserData;          /* User data parameter */
00431   FuncDef *pNext;           /* Next function with same name */
00432 };
00433 
00434 /*
00435 ** information about each column of an SQL table is held in an instance
00436 ** of this structure.
00437 */
00438 struct Column {
00439   char *zName;     /* Name of this column */
00440   char *zDflt;     /* Default value of this column */
00441   char *zType;     /* Data type for this column */
00442   u8 notNull;      /* True if there is a NOT NULL constraint */
00443   u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
00444   u8 sortOrder;    /* Some combination of SQLITE_SO_... values */
00445   u8 dottedName;   /* True if zName contains a "." character */
00446 };
00447 
00448 /*
00449 ** The allowed sort orders.
00450 **
00451 ** The TEXT and NUM values use bits that do not overlap with DESC and ASC.
00452 ** That way the two can be combined into a single number.
00453 */
00454 #define SQLITE_SO_UNK       0  /* Use the default collating type.  (SCT_NUM) */
00455 #define SQLITE_SO_TEXT      2  /* Sort using memcmp() */
00456 #define SQLITE_SO_NUM       4  /* Sort using sqliteCompare() */
00457 #define SQLITE_SO_TYPEMASK  6  /* Mask to extract the collating sequence */
00458 #define SQLITE_SO_ASC       0  /* Sort in ascending order */
00459 #define SQLITE_SO_DESC      1  /* Sort in descending order */
00460 #define SQLITE_SO_DIRMASK   1  /* Mask to extract the sort direction */
00461 
00462 /*
00463 ** Each SQL table is represented in memory by an instance of the
00464 ** following structure.
00465 **
00466 ** Table.zName is the name of the table.  The case of the original
00467 ** CREATE TABLE statement is stored, but case is not significant for
00468 ** comparisons.
00469 **
00470 ** Table.nCol is the number of columns in this table.  Table.aCol is a
00471 ** pointer to an array of Column structures, one for each column.
00472 **
00473 ** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
00474 ** the column that is that key.   Otherwise Table.iPKey is negative.  Note
00475 ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
00476 ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
00477 ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
00478 ** is generated for each row of the table.  Table.hasPrimKey is true if
00479 ** the table has any PRIMARY KEY, INTEGER or otherwise.
00480 **
00481 ** Table.tnum is the page number for the root BTree page of the table in the
00482 ** database file.  If Table.iDb is the index of the database table backend
00483 ** in sqlite.aDb[].  0 is for the main database and 1 is for the file that
00484 ** holds temporary tables and indices.  If Table.isTransient
00485 ** is true, then the table is stored in a file that is automatically deleted
00486 ** when the VDBE cursor to the table is closed.  In this case Table.tnum 
00487 ** refers VDBE cursor number that holds the table open, not to the root
00488 ** page number.  Transient tables are used to hold the results of a
00489 ** sub-query that appears instead of a real table name in the FROM clause 
00490 ** of a SELECT statement.
00491 */
00492 struct Table {
00493   char *zName;     /* Name of the table */
00494   int nCol;        /* Number of columns in this table */
00495   Column *aCol;    /* Information about each column */
00496   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
00497   Index *pIndex;   /* List of SQL indexes on this table. */
00498   int tnum;        /* Root BTree node for this table (see note above) */
00499   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
00500   u8 readOnly;     /* True if this table should not be written by the user */
00501   u8 iDb;          /* Index into sqlite.aDb[] of the backend for this table */
00502   u8 isTransient;  /* True if automatically deleted when VDBE finishes */
00503   u8 hasPrimKey;   /* True if there exists a primary key */
00504   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
00505   Trigger *pTrigger; /* List of SQL triggers on this table */
00506   FKey *pFKey;       /* Linked list of all foreign keys in this table */
00507 };
00508 
00509 /*
00510 ** Each foreign key constraint is an instance of the following structure.
00511 **
00512 ** A foreign key is associated with two tables.  The "from" table is
00513 ** the table that contains the REFERENCES clause that creates the foreign
00514 ** key.  The "to" table is the table that is named in the REFERENCES clause.
00515 ** Consider this example:
00516 **
00517 **     CREATE TABLE ex1(
00518 **       a INTEGER PRIMARY KEY,
00519 **       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
00520 **     );
00521 **
00522 ** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
00523 **
00524 ** Each REFERENCES clause generates an instance of the following structure
00525 ** which is attached to the from-table.  The to-table need not exist when
00526 ** the from-table is created.  The existance of the to-table is not checked
00527 ** until an attempt is made to insert data into the from-table.
00528 **
00529 ** The sqlite.aFKey hash table stores pointers to this structure
00530 ** given the name of a to-table.  For each to-table, all foreign keys
00531 ** associated with that table are on a linked list using the FKey.pNextTo
00532 ** field.
00533 */
00534 struct FKey {
00535   Table *pFrom;     /* The table that constains the REFERENCES clause */
00536   FKey *pNextFrom;  /* Next foreign key in pFrom */
00537   char *zTo;        /* Name of table that the key points to */
00538   FKey *pNextTo;    /* Next foreign key that points to zTo */
00539   int nCol;         /* Number of columns in this key */
00540   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
00541     int iFrom;         /* Index of column in pFrom */
00542     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
00543   } *aCol;          /* One entry for each of nCol column s */
00544   u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
00545   u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
00546   u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
00547   u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
00548 };
00549 
00550 /*
00551 ** SQLite supports many different ways to resolve a contraint
00552 ** error.  ROLLBACK processing means that a constraint violation
00553 ** causes the operation in process to fail and for the current transaction
00554 ** to be rolled back.  ABORT processing means the operation in process
00555 ** fails and any prior changes from that one operation are backed out,
00556 ** but the transaction is not rolled back.  FAIL processing means that
00557 ** the operation in progress stops and returns an error code.  But prior
00558 ** changes due to the same operation are not backed out and no rollback
00559 ** occurs.  IGNORE means that the particular row that caused the constraint
00560 ** error is not inserted or updated.  Processing continues and no error
00561 ** is returned.  REPLACE means that preexisting database rows that caused
00562 ** a UNIQUE constraint violation are removed so that the new insert or
00563 ** update can proceed.  Processing continues and no error is reported.
00564 **
00565 ** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
00566 ** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
00567 ** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
00568 ** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the
00569 ** referenced table row is propagated into the row that holds the
00570 ** foreign key.
00571 ** 
00572 ** The following symbolic values are used to record which type
00573 ** of action to take.
00574 */
00575 #define OE_None     0   /* There is no constraint to check */
00576 #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
00577 #define OE_Abort    2   /* Back out changes but do no rollback transaction */
00578 #define OE_Fail     3   /* Stop the operation but leave all prior changes */
00579 #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
00580 #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
00581 
00582 #define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
00583 #define OE_SetNull  7   /* Set the foreign key value to NULL */
00584 #define OE_SetDflt  8   /* Set the foreign key value to its default */
00585 #define OE_Cascade  9   /* Cascade the changes */
00586 
00587 #define OE_Default  99  /* Do whatever the default action is */
00588 
00589 /*
00590 ** Each SQL index is represented in memory by an
00591 ** instance of the following structure.
00592 **
00593 ** The columns of the table that are to be indexed are described
00594 ** by the aiColumn[] field of this structure.  For example, suppose
00595 ** we have the following table and index:
00596 **
00597 **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
00598 **     CREATE INDEX Ex2 ON Ex1(c3,c1);
00599 **
00600 ** In the Table structure describing Ex1, nCol==3 because there are
00601 ** three columns in the table.  In the Index structure describing
00602 ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
00603 ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
00604 ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
00605 ** The second column to be indexed (c1) has an index of 0 in
00606 ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
00607 **
00608 ** The Index.onError field determines whether or not the indexed columns
00609 ** must be unique and what to do if they are not.  When Index.onError=OE_None,
00610 ** it means this is not a unique index.  Otherwise it is a unique index
00611 ** and the value of Index.onError indicate the which conflict resolution 
00612 ** algorithm to employ whenever an attempt is made to insert a non-unique
00613 ** element.
00614 */
00615 struct Index {
00616   char *zName;     /* Name of this index */
00617   int nColumn;     /* Number of columns in the table used by this index */
00618   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
00619   Table *pTable;   /* The SQL table being indexed */
00620   int tnum;        /* Page containing root of this index in database file */
00621   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
00622   u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
00623   u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
00624   Index *pNext;    /* The next index associated with the same table */
00625 };
00626 
00627 /*
00628 ** Each token coming out of the lexer is an instance of
00629 ** this structure.  Tokens are also used as part of an expression.
00630 **
00631 ** Note if Token.z==0 then Token.dyn and Token.n are undefined and
00632 ** may contain random values.  Do not make any assuptions about Token.dyn
00633 ** and Token.n when Token.z==0.
00634 */
00635 struct Token {
00636   const char *z;      /* Text of the token.  Not NULL-terminated! */
00637   unsigned dyn  : 1;  /* True for malloced memory, false for static */
00638   unsigned n    : 31; /* Number of characters in this token */
00639 };
00640 
00641 /*
00642 ** Each node of an expression in the parse tree is an instance
00643 ** of this structure.
00644 **
00645 ** Expr.op is the opcode.  The integer parser token codes are reused
00646 ** as opcodes here.  For example, the parser defines TK_GE to be an integer
00647 ** code representing the ">=" operator.  This same integer code is reused
00648 ** to represent the greater-than-or-equal-to operator in the expression
00649 ** tree.
00650 **
00651 ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
00652 ** of argument if the expression is a function.
00653 **
00654 ** Expr.token is the operator token for this node.  For some expressions
00655 ** that have subexpressions, Expr.token can be the complete text that gave
00656 ** rise to the Expr.  In the latter case, the token is marked as being
00657 ** a compound token.
00658 **
00659 ** An expression of the form ID or ID.ID refers to a column in a table.
00660 ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
00661 ** the integer cursor number of a VDBE cursor pointing to that table and
00662 ** Expr.iColumn is the column number for the specific column.  If the
00663 ** expression is used as a result in an aggregate SELECT, then the
00664 ** value is also stored in the Expr.iAgg column in the aggregate so that
00665 ** it can be accessed after all aggregates are computed.
00666 **
00667 ** If the expression is a function, the Expr.iTable is an integer code
00668 ** representing which function.  If the expression is an unbound variable
00669 ** marker (a question mark character '?' in the original SQL) then the
00670 ** Expr.iTable holds the index number for that variable.
00671 **
00672 ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
00673 ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
00674 ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
00675 ** operand.
00676 */
00677 struct Expr {
00678   u8 op;                 /* Operation performed by this node */
00679   u8 dataType;           /* Either SQLITE_SO_TEXT or SQLITE_SO_NUM */
00680   u8 iDb;                /* Database referenced by this expression */
00681   u8 flags;              /* Various flags.  See below */
00682   Expr *pLeft, *pRight;  /* Left and right subnodes */
00683   ExprList *pList;       /* A list of expressions used as function arguments
00684                          ** or in "<expr> IN (<expr-list)" */
00685   Token token;           /* An operand token */
00686   Token span;            /* Complete text of the expression */
00687   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
00688                          ** iColumn-th field of the iTable-th table. */
00689   int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
00690                          ** result from the iAgg-th element of the aggregator */
00691   Select *pSelect;       /* When the expression is a sub-select.  Also the
00692                          ** right side of "<expr> IN (<select>)" */
00693 };
00694 
00695 /*
00696 ** The following are the meanings of bits in the Expr.flags field.
00697 */
00698 #define EP_FromJoin     0x0001  /* Originated in ON or USING clause of a join */
00699 
00700 /*
00701 ** These macros can be used to test, set, or clear bits in the 
00702 ** Expr.flags field.
00703 */
00704 #define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))
00705 #define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)
00706 #define ExprSetProperty(E,P)     (E)->flags|=(P)
00707 #define ExprClearProperty(E,P)   (E)->flags&=~(P)
00708 
00709 /*
00710 ** A list of expressions.  Each expression may optionally have a
00711 ** name.  An expr/name combination can be used in several ways, such
00712 ** as the list of "expr AS ID" fields following a "SELECT" or in the
00713 ** list of "ID = expr" items in an UPDATE.  A list of expressions can
00714 ** also be used as the argument to a function, in which case the a.zName
00715 ** field is not used.
00716 */
00717 struct ExprList {
00718   int nExpr;             /* Number of expressions on the list */
00719   int nAlloc;            /* Number of entries allocated below */
00720   struct ExprList_item {
00721     Expr *pExpr;           /* The list of expressions */
00722     char *zName;           /* Token associated with this expression */
00723     u8 sortOrder;          /* 1 for DESC or 0 for ASC */
00724     u8 isAgg;              /* True if this is an aggregate like count(*) */
00725     u8 done;               /* A flag to indicate when processing is finished */
00726   } *a;                  /* One entry for each expression */
00727 };
00728 
00729 /*
00730 ** An instance of this structure can hold a simple list of identifiers,
00731 ** such as the list "a,b,c" in the following statements:
00732 **
00733 **      INSERT INTO t(a,b,c) VALUES ...;
00734 **      CREATE INDEX idx ON t(a,b,c);
00735 **      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
00736 **
00737 ** The IdList.a.idx field is used when the IdList represents the list of
00738 ** column names after a table name in an INSERT statement.  In the statement
00739 **
00740 **     INSERT INTO t(a,b,c) ...
00741 **
00742 ** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
00743 */
00744 struct IdList {
00745   int nId;         /* Number of identifiers on the list */
00746   int nAlloc;      /* Number of entries allocated for a[] below */
00747   struct IdList_item {
00748     char *zName;      /* Name of the identifier */
00749     int idx;          /* Index in some Table.aCol[] of a column named zName */
00750   } *a;
00751 };
00752 
00753 /*
00754 ** The following structure describes the FROM clause of a SELECT statement.
00755 ** Each table or subquery in the FROM clause is a separate element of
00756 ** the SrcList.a[] array.
00757 **
00758 ** With the addition of multiple database support, the following structure
00759 ** can also be used to describe a particular table such as the table that
00760 ** is modified by an INSERT, DELETE, or UPDATE statement.  In standard SQL,
00761 ** such a table must be a simple name: ID.  But in SQLite, the table can
00762 ** now be identified by a database name, a dot, then the table name: ID.ID.
00763 */
00764 struct SrcList {
00765   u16 nSrc;        /* Number of tables or subqueries in the FROM clause */
00766   u16 nAlloc;      /* Number of entries allocated in a[] below */
00767   struct SrcList_item {
00768     char *zDatabase;  /* Name of database holding this table */
00769     char *zName;      /* Name of the table */
00770     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
00771     Table *pTab;      /* An SQL table corresponding to zName */
00772     Select *pSelect;  /* A SELECT statement used in place of a table name */
00773     int jointype;     /* Type of join between this table and the next */
00774     int iCursor;      /* The VDBE cursor number used to access this table */
00775     Expr *pOn;        /* The ON clause of a join */
00776     IdList *pUsing;   /* The USING clause of a join */
00777   } a[1];             /* One entry for each identifier on the list */
00778 };
00779 
00780 /*
00781 ** Permitted values of the SrcList.a.jointype field
00782 */
00783 #define JT_INNER     0x0001    /* Any kind of inner or cross join */
00784 #define JT_NATURAL   0x0002    /* True for a "natural" join */
00785 #define JT_LEFT      0x0004    /* Left outer join */
00786 #define JT_RIGHT     0x0008    /* Right outer join */
00787 #define JT_OUTER     0x0010    /* The "OUTER" keyword is present */
00788 #define JT_ERROR     0x0020    /* unknown or unsupported join type */
00789 
00790 /*
00791 ** For each nested loop in a WHERE clause implementation, the WhereInfo
00792 ** structure contains a single instance of this structure.  This structure
00793 ** is intended to be private the the where.c module and should not be
00794 ** access or modified by other modules.
00795 */
00796 struct WhereLevel {
00797   int iMem;            /* Memory cell used by this level */
00798   Index *pIdx;         /* Index used */
00799   int iCur;            /* Cursor number used for this index */
00800   int score;           /* How well this indexed scored */
00801   int brk;             /* Jump here to break out of the loop */
00802   int cont;            /* Jump here to continue with the next loop cycle */
00803   int op, p1, p2;      /* Opcode used to terminate the loop */
00804   int iLeftJoin;       /* Memory cell used to implement LEFT OUTER JOIN */
00805   int top;             /* First instruction of interior of the loop */
00806   int inOp, inP1, inP2;/* Opcode used to implement an IN operator */
00807   int bRev;            /* Do the scan in the reverse direction */
00808 };
00809 
00810 /*
00811 ** The WHERE clause processing routine has two halves.  The
00812 ** first part does the start of the WHERE loop and the second
00813 ** half does the tail of the WHERE loop.  An instance of
00814 ** this structure is returned by the first half and passed
00815 ** into the second half to give some continuity.
00816 */
00817 struct WhereInfo {
00818   Parse *pParse;
00819   SrcList *pTabList;   /* List of tables in the join */
00820   int iContinue;       /* Jump here to continue with next record */
00821   int iBreak;          /* Jump here to break out of the loop */
00822   int nLevel;          /* Number of nested loop */
00823   int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
00824   int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
00825   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
00826 };
00827 
00828 /*
00829 ** An instance of the following structure contains all information
00830 ** needed to generate code for a single SELECT statement.
00831 **
00832 ** The zSelect field is used when the Select structure must be persistent.
00833 ** Normally, the expression tree points to tokens in the original input
00834 ** string that encodes the select.  But if the Select structure must live
00835 ** longer than its input string (for example when it is used to describe
00836 ** a VIEW) we have to make a copy of the input string so that the nodes
00837 ** of the expression tree will have something to point to.  zSelect is used
00838 ** to hold that copy.
00839 **
00840 ** nLimit is set to -1 if there is no LIMIT clause.  nOffset is set to 0.
00841 ** If there is a LIMIT clause, the parser sets nLimit to the value of the
00842 ** limit and nOffset to the value of the offset (or 0 if there is not
00843 ** offset).  But later on, nLimit and nOffset become the memory locations
00844 ** in the VDBE that record the limit and offset counters.
00845 */
00846 struct Select {
00847   ExprList *pEList;      /* The fields of the result */
00848   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
00849   u8 isDistinct;         /* True if the DISTINCT keyword is present */
00850   SrcList *pSrc;         /* The FROM clause */
00851   Expr *pWhere;          /* The WHERE clause */
00852   ExprList *pGroupBy;    /* The GROUP BY clause */
00853   Expr *pHaving;         /* The HAVING clause */
00854   ExprList *pOrderBy;    /* The ORDER BY clause */
00855   Select *pPrior;        /* Prior select in a compound select statement */
00856   int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
00857   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
00858   char *zSelect;         /* Complete text of the SELECT command */
00859 };
00860 
00861 /*
00862 ** The results of a select can be distributed in several ways.
00863 */
00864 #define SRT_Callback     1  /* Invoke a callback with each row of result */
00865 #define SRT_Mem          2  /* Store result in a memory cell */
00866 #define SRT_Set          3  /* Store result as unique keys in a table */
00867 #define SRT_Union        5  /* Store result as keys in a table */
00868 #define SRT_Except       6  /* Remove result from a UNION table */
00869 #define SRT_Table        7  /* Store result as data with a unique key */
00870 #define SRT_TempTable    8  /* Store result in a trasient table */
00871 #define SRT_Discard      9  /* Do not save the results anywhere */
00872 #define SRT_Sorter      10  /* Store results in the sorter */
00873 #define SRT_Subroutine  11  /* Call a subroutine to handle results */
00874 
00875 /*
00876 ** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
00877 ** we have to do some additional analysis of expressions.  An instance
00878 ** of the following structure holds information about a single subexpression
00879 ** somewhere in the SELECT statement.  An array of these structures holds
00880 ** all the information we need to generate code for aggregate
00881 ** expressions.
00882 **
00883 ** Note that when analyzing a SELECT containing aggregates, both
00884 ** non-aggregate field variables and aggregate functions are stored
00885 ** in the AggExpr array of the Parser structure.
00886 **
00887 ** The pExpr field points to an expression that is part of either the
00888 ** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
00889 ** clause.  The expression will be freed when those clauses are cleaned
00890 ** up.  Do not try to delete the expression attached to AggExpr.pExpr.
00891 **
00892 ** If AggExpr.pExpr==0, that means the expression is "count(*)".
00893 */
00894 struct AggExpr {
00895   int isAgg;        /* if TRUE contains an aggregate function */
00896   Expr *pExpr;      /* The expression */
00897   FuncDef *pFunc;   /* Information about the aggregate function */
00898 };
00899 
00900 /*
00901 ** An SQL parser context.  A copy of this structure is passed through
00902 ** the parser and down into all the parser action routine in order to
00903 ** carry around information that is global to the entire parse.
00904 */
00905 struct Parse {
00906   sqlite *db;          /* The main database structure */
00907   int rc;              /* Return code from execution */
00908   char *zErrMsg;       /* An error message */
00909   Token sErrToken;     /* The token at which the error occurred */
00910   Token sFirstToken;   /* The first token parsed */
00911   Token sLastToken;    /* The last token parsed */
00912   const char *zTail;   /* All SQL text past the last semicolon parsed */
00913   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
00914   Vdbe *pVdbe;         /* An engine for executing database bytecode */
00915   u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
00916   u8 explain;          /* True if the EXPLAIN flag is found on the query */
00917   u8 nameClash;        /* A permanent table name clashes with temp table name */
00918   u8 useAgg;           /* If true, extract field values from the aggregator
00919                        ** while generating expressions.  Normally false */
00920   int nErr;            /* Number of errors seen */
00921   int nTab;            /* Number of previously allocated VDBE cursors */
00922   int nMem;            /* Number of memory cells used so far */
00923   int nSet;            /* Number of sets used so far */
00924   int nAgg;            /* Number of aggregate expressions */
00925   int nVar;            /* Number of '?' variables seen in the SQL so far */
00926   AggExpr *aAgg;       /* An array of aggregate expressions */
00927   const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
00928   Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
00929   TriggerStack *trigStack;  /* Trigger actions being coded */
00930 };
00931 
00932 /*
00933 ** An instance of the following structure can be declared on a stack and used
00934 ** to save the Parse.zAuthContext value so that it can be restored later.
00935 */
00936 struct AuthContext {
00937   const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
00938   Parse *pParse;              /* The Parse structure */
00939 };
00940 
00941 /*
00942 ** Bitfield flags for P2 value in OP_PutIntKey and OP_Delete
00943 */
00944 #define OPFLAG_NCHANGE   1    /* Set to update db->nChange */
00945 #define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */
00946 #define OPFLAG_CSCHANGE  4    /* Set to update db->csChange */
00947 
00948 /*
00949  * Each trigger present in the database schema is stored as an instance of
00950  * struct Trigger. 
00951  *
00952  * Pointers to instances of struct Trigger are stored in two ways.
00953  * 1. In the "trigHash" hash table (part of the sqlite* that represents the 
00954  *    database). This allows Trigger structures to be retrieved by name.
00955  * 2. All triggers associated with a single table form a linked list, using the
00956  *    pNext member of struct Trigger. A pointer to the first element of the
00957  *    linked list is stored as the "pTrigger" member of the associated
00958  *    struct Table.
00959  *
00960  * The "step_list" member points to the first element of a linked list
00961  * containing the SQL statements specified as the trigger program.
00962  */
00963 struct Trigger {
00964   char *name;             /* The name of the trigger                        */
00965   char *table;            /* The table or view to which the trigger applies */
00966   u8 iDb;                 /* Database containing this trigger               */
00967   u8 iTabDb;              /* Database containing Trigger.table              */
00968   u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
00969   u8 tr_tm;               /* One of TK_BEFORE, TK_AFTER */
00970   Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
00971   IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
00972                              the <column-list> is stored here */
00973   int foreach;            /* One of TK_ROW or TK_STATEMENT */
00974   Token nameToken;        /* Token containing zName. Use during parsing only */
00975 
00976   TriggerStep *step_list; /* Link list of trigger program steps             */
00977   Trigger *pNext;         /* Next trigger associated with the table */
00978 };
00979 
00980 /*
00981  * An instance of struct TriggerStep is used to store a single SQL statement
00982  * that is a part of a trigger-program. 
00983  *
00984  * Instances of struct TriggerStep are stored in a singly linked list (linked
00985  * using the "pNext" member) referenced by the "step_list" member of the 
00986  * associated struct Trigger instance. The first element of the linked list is
00987  * the first step of the trigger-program.
00988  * 
00989  * The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
00990  * "SELECT" statement. The meanings of the other members is determined by the 
00991  * value of "op" as follows:
00992  *
00993  * (op == TK_INSERT)
00994  * orconf    -> stores the ON CONFLICT algorithm
00995  * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then
00996  *              this stores a pointer to the SELECT statement. Otherwise NULL.
00997  * target    -> A token holding the name of the table to insert into.
00998  * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
00999  *              this stores values to be inserted. Otherwise NULL.
01000  * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ... 
01001  *              statement, then this stores the column-names to be
01002  *              inserted into.
01003  *
01004  * (op == TK_DELETE)
01005  * target    -> A token holding the name of the table to delete from.
01006  * pWhere    -> The WHERE clause of the DELETE statement if one is specified.
01007  *              Otherwise NULL.
01008  * 
01009  * (op == TK_UPDATE)
01010  * target    -> A token holding the name of the table to update rows of.
01011  * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
01012  *              Otherwise NULL.
01013  * pExprList -> A list of the columns to update and the expressions to update
01014  *              them to. See sqliteUpdate() documentation of "pChanges"
01015  *              argument.
01016  * 
01017  */
01018 struct TriggerStep {
01019   int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
01020   int orconf;          /* OE_Rollback etc. */
01021   Trigger *pTrig;      /* The trigger that this step is a part of */
01022 
01023   Select *pSelect;     /* Valid for SELECT and sometimes 
01024                           INSERT steps (when pExprList == 0) */
01025   Token target;        /* Valid for DELETE, UPDATE, INSERT steps */
01026   Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
01027   ExprList *pExprList; /* Valid for UPDATE statements and sometimes 
01028                            INSERT steps (when pSelect == 0)         */
01029   IdList *pIdList;     /* Valid for INSERT statements only */
01030 
01031   TriggerStep * pNext; /* Next in the link-list */
01032 };
01033 
01034 /*
01035  * An instance of struct TriggerStack stores information required during code
01036  * generation of a single trigger program. While the trigger program is being
01037  * coded, its associated TriggerStack instance is pointed to by the
01038  * "pTriggerStack" member of the Parse structure.
01039  *
01040  * The pTab member points to the table that triggers are being coded on. The 
01041  * newIdx member contains the index of the vdbe cursor that points at the temp
01042  * table that stores the new.* references. If new.* references are not valid
01043  * for the trigger being coded (for example an ON DELETE trigger), then newIdx
01044  * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
01045  *
01046  * The ON CONFLICT policy to be used for the trigger program steps is stored 
01047  * as the orconf member. If this is OE_Default, then the ON CONFLICT clause 
01048  * specified for individual triggers steps is used.
01049  *
01050  * struct TriggerStack has a "pNext" member, to allow linked lists to be
01051  * constructed. When coding nested triggers (triggers fired by other triggers)
01052  * each nested trigger stores its parent trigger's TriggerStack as the "pNext" 
01053  * pointer. Once the nested trigger has been coded, the pNext value is restored
01054  * to the pTriggerStack member of the Parse stucture and coding of the parent
01055  * trigger continues.
01056  *
01057  * Before a nested trigger is coded, the linked list pointed to by the 
01058  * pTriggerStack is scanned to ensure that the trigger is not about to be coded
01059  * recursively. If this condition is detected, the nested trigger is not coded.
01060  */
01061 struct TriggerStack {
01062   Table *pTab;         /* Table that triggers are currently being coded on */
01063   int newIdx;          /* Index of vdbe cursor to "new" temp table */
01064   int oldIdx;          /* Index of vdbe cursor to "old" temp table */
01065   int orconf;          /* Current orconf policy */
01066   int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */
01067   Trigger *pTrigger;   /* The trigger currently being coded */
01068   TriggerStack *pNext; /* Next trigger down on the trigger stack */
01069 };
01070 
01071 /*
01072 ** The following structure contains information used by the sqliteFix...
01073 ** routines as they walk the parse tree to make database references
01074 ** explicit.  
01075 */
01076 typedef struct DbFixer DbFixer;
01077 struct DbFixer {
01078   Parse *pParse;      /* The parsing context.  Error messages written here */
01079   const char *zDb;    /* Make sure all objects are contained in this database */
01080   const char *zType;  /* Type of the container - used for error messages */
01081   const Token *pName; /* Name of the container - used for error messages */
01082 };
01083 
01084 /*
01085  * This global flag is set for performance testing of triggers. When it is set
01086  * SQLite will perform the overhead of building new and old trigger references 
01087  * even when no triggers exist
01088  */
01089 extern int always_code_trigger_setup;
01090 
01091 /*
01092 ** Internal function prototypes
01093 */
01094 int sqliteStrICmp(const char *, const char *);
01095 int sqliteStrNICmp(const char *, const char *, int);
01096 int sqliteHashNoCase(const char *, int);
01097 int sqliteIsNumber(const char*);
01098 int sqliteCompare(const char *, const char *);
01099 int sqliteSortCompare(const char *, const char *);
01100 void sqliteRealToSortable(double r, char *);
01101 #ifdef MEMORY_DEBUG
01102   void *sqliteMalloc_(int,int,char*,int);
01103   void sqliteFree_(void*,char*,int);
01104   void *sqliteRealloc_(void*,int,char*,int);
01105   char *sqliteStrDup_(const char*,char*,int);
01106   char *sqliteStrNDup_(const char*, int,char*,int);
01107   void sqliteCheckMemory(void*,int);
01108 #else
01109   void *sqliteMalloc(int);
01110   void *sqliteMallocRaw(int);
01111   void sqliteFree(void*);
01112   void *sqliteRealloc(void*,int);
01113   char *sqliteStrDup(const char*);
01114   char *sqliteStrNDup(const char*, int);
01115 # define sqliteCheckMemory(a,b)
01116 #endif
01117 char *sqliteMPrintf(const char*, ...);
01118 char *sqliteVMPrintf(const char*, va_list);
01119 void sqliteSetString(char **, const char *, ...);
01120 void sqliteSetNString(char **, ...);
01121 void sqliteErrorMsg(Parse*, const char*, ...);
01122 void sqliteDequote(char*);
01123 int sqliteKeywordCode(const char*, int);
01124 int sqliteRunParser(Parse*, const char*, char **);
01125 void sqliteExec(Parse*);
01126 Expr *sqliteExpr(int, Expr*, Expr*, Token*);
01127 void sqliteExprSpan(Expr*,Token*,Token*);
01128 Expr *sqliteExprFunction(ExprList*, Token*);
01129 void sqliteExprDelete(Expr*);
01130 ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
01131 void sqliteExprListDelete(ExprList*);
01132 int sqliteInit(sqlite*, char**);
01133 void sqlitePragma(Parse*,Token*,Token*,int);
01134 void sqliteResetInternalSchema(sqlite*, int);
01135 void sqliteBeginParse(Parse*,int);
01136 void sqliteRollbackInternalChanges(sqlite*);
01137 void sqliteCommitInternalChanges(sqlite*);
01138 Table *sqliteResultSetOfSelect(Parse*,char*,Select*);
01139 void sqliteOpenMasterTable(Vdbe *v, int);
01140 void sqliteStartTable(Parse*,Token*,Token*,int,int);
01141 void sqliteAddColumn(Parse*,Token*);
01142 void sqliteAddNotNull(Parse*, int);
01143 void sqliteAddPrimaryKey(Parse*, IdList*, int);
01144 void sqliteAddColumnType(Parse*,Token*,Token*);
01145 void sqliteAddDefaultValue(Parse*,Token*,int);
01146 int sqliteCollateType(const char*, int);
01147 void sqliteAddCollateType(Parse*, int);
01148 void sqliteEndTable(Parse*,Token*,Select*);
01149 void sqliteCreateView(Parse*,Token*,Token*,Select*,int);
01150 int sqliteViewGetColumnNames(Parse*,Table*);
01151 void sqliteDropTable(Parse*, Token*, int);
01152 void sqliteDeleteTable(sqlite*, Table*);
01153 void sqliteInsert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
01154 IdList *sqliteIdListAppend(IdList*, Token*);
01155 int sqliteIdListIndex(IdList*,const char*);
01156 SrcList *sqliteSrcListAppend(SrcList*, Token*, Token*);
01157 void sqliteSrcListAddAlias(SrcList*, Token*);
01158 void sqliteSrcListAssignCursors(Parse*, SrcList*);
01159 void sqliteIdListDelete(IdList*);
01160 void sqliteSrcListDelete(SrcList*);
01161 void sqliteCreateIndex(Parse*,Token*,SrcList*,IdList*,int,Token*,Token*);
01162 void sqliteDropIndex(Parse*, SrcList*);
01163 void sqliteAddKeyType(Vdbe*, ExprList*);
01164 void sqliteAddIdxKeyType(Vdbe*, Index*);
01165 int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
01166 Select *sqliteSelectNew(ExprList*,SrcList*,Expr*,ExprList*,Expr*,ExprList*,
01167                         int,int,int);
01168 void sqliteSelectDelete(Select*);
01169 void sqliteSelectUnbind(Select*);
01170 Table *sqliteSrcListLookup(Parse*, SrcList*);
01171 int sqliteIsReadOnly(Parse*, Table*, int);
01172 void sqliteDeleteFrom(Parse*, SrcList*, Expr*);
01173 void sqliteUpdate(Parse*, SrcList*, ExprList*, Expr*, int);
01174 WhereInfo *sqliteWhereBegin(Parse*, SrcList*, Expr*, int, ExprList**);
01175 void sqliteWhereEnd(WhereInfo*);
01176 void sqliteExprCode(Parse*, Expr*);
01177 int sqliteExprCodeExprList(Parse*, ExprList*, int);
01178 void sqliteExprIfTrue(Parse*, Expr*, int, int);
01179 void sqliteExprIfFalse(Parse*, Expr*, int, int);
01180 Table *sqliteFindTable(sqlite*,const char*, const char*);
01181 Table *sqliteLocateTable(Parse*,const char*, const char*);
01182 Index *sqliteFindIndex(sqlite*,const char*, const char*);
01183 void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
01184 void sqliteCopy(Parse*, SrcList*, Token*, Token*, int);
01185 void sqliteVacuum(Parse*, Token*);
01186 int sqliteRunVacuum(char**, sqlite*);
01187 int sqliteGlobCompare(const unsigned char*,const unsigned char*);
01188 int sqliteLikeCompare(const unsigned char*,const unsigned char*);
01189 char *sqliteTableNameFromToken(Token*);
01190 int sqliteExprCheck(Parse*, Expr*, int, int*);
01191 int sqliteExprType(Expr*);
01192 int sqliteExprCompare(Expr*, Expr*);
01193 int sqliteFuncId(Token*);
01194 int sqliteExprResolveIds(Parse*, SrcList*, ExprList*, Expr*);
01195 int sqliteExprAnalyzeAggregates(Parse*, Expr*);
01196 Vdbe *sqliteGetVdbe(Parse*);
01197 void sqliteRandomness(int, void*);
01198 void sqliteRollbackAll(sqlite*);
01199 void sqliteCodeVerifySchema(Parse*, int);
01200 void sqliteBeginTransaction(Parse*, int);
01201 void sqliteCommitTransaction(Parse*);
01202 void sqliteRollbackTransaction(Parse*);
01203 int sqliteExprIsConstant(Expr*);
01204 int sqliteExprIsInteger(Expr*, int*);
01205 int sqliteIsRowid(const char*);
01206 void sqliteGenerateRowDelete(sqlite*, Vdbe*, Table*, int, int);
01207 void sqliteGenerateRowIndexDelete(sqlite*, Vdbe*, Table*, int, char*);
01208 void sqliteGenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
01209 void sqliteCompleteInsertion(Parse*, Table*, int, char*, int, int, int);
01210 int sqliteOpenTableAndIndices(Parse*, Table*, int);
01211 void sqliteBeginWriteOperation(Parse*, int, int);
01212 void sqliteEndWriteOperation(Parse*);
01213 Expr *sqliteExprDup(Expr*);
01214 void sqliteTokenCopy(Token*, Token*);
01215 ExprList *sqliteExprListDup(ExprList*);
01216 SrcList *sqliteSrcListDup(SrcList*);
01217 IdList *sqliteIdListDup(IdList*);
01218 Select *sqliteSelectDup(Select*);
01219 FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
01220 void sqliteRegisterBuiltinFunctions(sqlite*);
01221 void sqliteRegisterDateTimeFunctions(sqlite*);
01222 int sqliteSafetyOn(sqlite*);
01223 int sqliteSafetyOff(sqlite*);
01224 int sqliteSafetyCheck(sqlite*);
01225 void sqliteChangeCookie(sqlite*, Vdbe*);
01226 void sqliteBeginTrigger(Parse*, Token*,int,int,IdList*,SrcList*,int,Expr*,int);
01227 void sqliteFinishTrigger(Parse*, TriggerStep*, Token*);
01228 void sqliteDropTrigger(Parse*, SrcList*);
01229 void sqliteDropTriggerPtr(Parse*, Trigger*, int);
01230 int sqliteTriggersExist(Parse* , Trigger* , int , int , int, ExprList*);
01231 int sqliteCodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 
01232                          int, int);
01233 void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
01234 void sqliteDeleteTriggerStep(TriggerStep*);
01235 TriggerStep *sqliteTriggerSelectStep(Select*);
01236 TriggerStep *sqliteTriggerInsertStep(Token*, IdList*, ExprList*, Select*, int);
01237 TriggerStep *sqliteTriggerUpdateStep(Token*, ExprList*, Expr*, int);
01238 TriggerStep *sqliteTriggerDeleteStep(Token*, Expr*);
01239 void sqliteDeleteTrigger(Trigger*);
01240 int sqliteJoinType(Parse*, Token*, Token*, Token*);
01241 void sqliteCreateForeignKey(Parse*, IdList*, Token*, IdList*, int);
01242 void sqliteDeferForeignKey(Parse*, int);
01243 #ifndef SQLITE_OMIT_AUTHORIZATION
01244   void sqliteAuthRead(Parse*,Expr*,SrcList*);
01245   int sqliteAuthCheck(Parse*,int, const char*, const char*, const char*);
01246   void sqliteAuthContextPush(Parse*, AuthContext*, const char*);
01247   void sqliteAuthContextPop(AuthContext*);
01248 #else
01249 # define sqliteAuthRead(a,b,c)
01250 # define sqliteAuthCheck(a,b,c,d,e)    SQLITE_OK
01251 # define sqliteAuthContextPush(a,b,c)
01252 # define sqliteAuthContextPop(a)  ((void)(a))
01253 #endif
01254 void sqliteAttach(Parse*, Token*, Token*, Token*);
01255 void sqliteDetach(Parse*, Token*);
01256 int sqliteBtreeFactory(const sqlite *db, const char *zFilename,
01257                        int mode, int nPg, Btree **ppBtree);
01258 int sqliteFixInit(DbFixer*, Parse*, int, const char*, const Token*);
01259 int sqliteFixSrcList(DbFixer*, SrcList*);
01260 int sqliteFixSelect(DbFixer*, Select*);
01261 int sqliteFixExpr(DbFixer*, Expr*);
01262 int sqliteFixExprList(DbFixer*, ExprList*);
01263 int sqliteFixTriggerStep(DbFixer*, TriggerStep*);
01264 double sqliteAtoF(const char *z, const char **);
01265 char *sqlite_snprintf(int,char*,const char*,...);
01266 int sqliteFitsIn32Bits(const char *);
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