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1 /* |
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2 ** 2003 September 6 |
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3 ** |
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4 ** The author disclaims copyright to this source code. In place of |
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5 ** a legal notice, here is a blessing: |
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6 ** |
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7 ** May you do good and not evil. |
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8 ** May you find forgiveness for yourself and forgive others. |
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9 ** May you share freely, never taking more than you give. |
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10 ** |
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11 ************************************************************************* |
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12 ** This is the header file for information that is private to the |
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13 ** VDBE. This information used to all be at the top of the single |
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14 ** source code file "vdbe.c". When that file became too big (over |
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15 ** 6000 lines long) it was split up into several smaller files and |
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16 ** this header information was factored out. |
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17 ** |
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18 ** $Id: vdbeInt.h,v 1.155 2008/10/07 23:46:38 drh Exp $ |
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19 */ |
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20 #ifndef _VDBEINT_H_ |
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21 #define _VDBEINT_H_ |
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22 |
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23 /* |
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24 ** intToKey() and keyToInt() used to transform the rowid. But with |
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25 ** the latest versions of the design they are no-ops. |
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26 */ |
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27 #define keyToInt(X) (X) |
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28 #define intToKey(X) (X) |
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29 |
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30 |
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31 /* |
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32 ** SQL is translated into a sequence of instructions to be |
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33 ** executed by a virtual machine. Each instruction is an instance |
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34 ** of the following structure. |
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35 */ |
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36 typedef struct VdbeOp Op; |
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37 |
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38 /* |
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39 ** Boolean values |
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40 */ |
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41 typedef unsigned char Bool; |
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42 |
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43 /* |
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44 ** A cursor is a pointer into a single BTree within a database file. |
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45 ** The cursor can seek to a BTree entry with a particular key, or |
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46 ** loop over all entries of the Btree. You can also insert new BTree |
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47 ** entries or retrieve the key or data from the entry that the cursor |
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48 ** is currently pointing to. |
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49 ** |
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50 ** Every cursor that the virtual machine has open is represented by an |
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51 ** instance of the following structure. |
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52 ** |
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53 ** If the Cursor.isTriggerRow flag is set it means that this cursor is |
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54 ** really a single row that represents the NEW or OLD pseudo-table of |
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55 ** a row trigger. The data for the row is stored in Cursor.pData and |
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56 ** the rowid is in Cursor.iKey. |
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57 */ |
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58 struct Cursor { |
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59 BtCursor *pCursor; /* The cursor structure of the backend */ |
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60 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ |
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61 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ |
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62 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ |
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63 Bool zeroed; /* True if zeroed out and ready for reuse */ |
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64 Bool rowidIsValid; /* True if lastRowid is valid */ |
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65 Bool atFirst; /* True if pointing to first entry */ |
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66 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ |
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67 Bool nullRow; /* True if pointing to a row with no data */ |
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68 Bool nextRowidValid; /* True if the nextRowid field is valid */ |
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69 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ |
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70 Bool ephemPseudoTable; |
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71 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ |
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72 Bool isTable; /* True if a table requiring integer keys */ |
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73 Bool isIndex; /* True if an index containing keys only - no data */ |
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74 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ |
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75 Btree *pBt; /* Separate file holding temporary table */ |
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76 int nData; /* Number of bytes in pData */ |
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77 char *pData; /* Data for a NEW or OLD pseudo-table */ |
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78 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ |
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79 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ |
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80 int nField; /* Number of fields in the header */ |
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81 i64 seqCount; /* Sequence counter */ |
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82 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ |
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83 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ |
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84 |
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85 /* Cached information about the header for the data record that the |
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86 ** cursor is currently pointing to. Only valid if cacheValid is true. |
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87 ** aRow might point to (ephemeral) data for the current row, or it might |
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88 ** be NULL. |
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89 */ |
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90 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ |
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91 int payloadSize; /* Total number of bytes in the record */ |
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92 u32 *aType; /* Type values for all entries in the record */ |
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93 u32 *aOffset; /* Cached offsets to the start of each columns data */ |
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94 u8 *aRow; /* Data for the current row, if all on one page */ |
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95 }; |
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96 typedef struct Cursor Cursor; |
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97 |
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98 /* |
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99 ** A value for Cursor.cacheValid that means the cache is always invalid. |
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100 */ |
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101 #define CACHE_STALE 0 |
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102 |
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103 /* |
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104 ** Internally, the vdbe manipulates nearly all SQL values as Mem |
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105 ** structures. Each Mem struct may cache multiple representations (string, |
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106 ** integer etc.) of the same value. A value (and therefore Mem structure) |
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107 ** has the following properties: |
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108 ** |
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109 ** Each value has a manifest type. The manifest type of the value stored |
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110 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is |
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111 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or |
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112 ** SQLITE_BLOB. |
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113 */ |
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114 struct Mem { |
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115 union { |
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116 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ |
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117 FuncDef *pDef; /* Used only when flags==MEM_Agg */ |
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118 } u; |
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119 double r; /* Real value */ |
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120 sqlite3 *db; /* The associated database connection */ |
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121 char *z; /* String or BLOB value */ |
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122 int n; /* Number of characters in string value, excluding '\0' */ |
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123 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ |
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124 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ |
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125 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ |
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126 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ |
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127 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ |
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128 }; |
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129 |
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130 /* One or more of the following flags are set to indicate the validOK |
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131 ** representations of the value stored in the Mem struct. |
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132 ** |
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133 ** If the MEM_Null flag is set, then the value is an SQL NULL value. |
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134 ** No other flags may be set in this case. |
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135 ** |
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136 ** If the MEM_Str flag is set then Mem.z points at a string representation. |
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137 ** Usually this is encoded in the same unicode encoding as the main |
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138 ** database (see below for exceptions). If the MEM_Term flag is also |
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139 ** set, then the string is nul terminated. The MEM_Int and MEM_Real |
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140 ** flags may coexist with the MEM_Str flag. |
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141 ** |
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142 ** Multiple of these values can appear in Mem.flags. But only one |
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143 ** at a time can appear in Mem.type. |
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144 */ |
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145 #define MEM_Null 0x0001 /* Value is NULL */ |
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146 #define MEM_Str 0x0002 /* Value is a string */ |
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147 #define MEM_Int 0x0004 /* Value is an integer */ |
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148 #define MEM_Real 0x0008 /* Value is a real number */ |
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149 #define MEM_Blob 0x0010 /* Value is a BLOB */ |
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150 |
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151 #define MemSetTypeFlag(p, f) \ |
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152 ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f) |
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153 |
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154 /* Whenever Mem contains a valid string or blob representation, one of |
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155 ** the following flags must be set to determine the memory management |
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156 ** policy for Mem.z. The MEM_Term flag tells us whether or not the |
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157 ** string is \000 or \u0000 terminated |
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158 */ |
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159 #define MEM_Term 0x0020 /* String rep is nul terminated */ |
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160 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ |
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161 #define MEM_Static 0x0080 /* Mem.z points to a static string */ |
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162 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ |
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163 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ |
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164 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */ |
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165 |
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166 #ifdef SQLITE_OMIT_INCRBLOB |
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167 #undef MEM_Zero |
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168 #define MEM_Zero 0x0000 |
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169 #endif |
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170 |
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171 |
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172 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains |
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173 ** additional information about auxiliary information bound to arguments |
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174 ** of the function. This is used to implement the sqlite3_get_auxdata() |
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175 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data |
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176 ** that can be associated with a constant argument to a function. This |
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177 ** allows functions such as "regexp" to compile their constant regular |
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178 ** expression argument once and reused the compiled code for multiple |
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179 ** invocations. |
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180 */ |
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181 struct VdbeFunc { |
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182 FuncDef *pFunc; /* The definition of the function */ |
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183 int nAux; /* Number of entries allocated for apAux[] */ |
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184 struct AuxData { |
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185 void *pAux; /* Aux data for the i-th argument */ |
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186 void (*xDelete)(void *); /* Destructor for the aux data */ |
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187 } apAux[1]; /* One slot for each function argument */ |
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188 }; |
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189 |
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190 /* |
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191 ** The "context" argument for a installable function. A pointer to an |
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192 ** instance of this structure is the first argument to the routines used |
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193 ** implement the SQL functions. |
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194 ** |
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195 ** There is a typedef for this structure in sqlite.h. So all routines, |
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196 ** even the public interface to SQLite, can use a pointer to this structure. |
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197 ** But this file is the only place where the internal details of this |
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198 ** structure are known. |
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199 ** |
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200 ** This structure is defined inside of vdbeInt.h because it uses substructures |
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201 ** (Mem) which are only defined there. |
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202 */ |
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203 struct sqlite3_context { |
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204 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ |
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205 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ |
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206 Mem s; /* The return value is stored here */ |
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207 Mem *pMem; /* Memory cell used to store aggregate context */ |
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208 int isError; /* Error code returned by the function. */ |
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209 CollSeq *pColl; /* Collating sequence */ |
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210 }; |
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211 |
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212 /* |
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213 ** A Set structure is used for quick testing to see if a value |
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214 ** is part of a small set. Sets are used to implement code like |
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215 ** this: |
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216 ** x.y IN ('hi','hoo','hum') |
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217 */ |
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218 typedef struct Set Set; |
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219 struct Set { |
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220 Hash hash; /* A set is just a hash table */ |
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221 HashElem *prev; /* Previously accessed hash elemen */ |
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222 }; |
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223 |
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224 /* |
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225 ** A FifoPage structure holds a single page of valves. Pages are arranged |
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226 ** in a list. |
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227 */ |
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228 typedef struct FifoPage FifoPage; |
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229 struct FifoPage { |
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230 int nSlot; /* Number of entries aSlot[] */ |
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231 int iWrite; /* Push the next value into this entry in aSlot[] */ |
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232 int iRead; /* Read the next value from this entry in aSlot[] */ |
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233 FifoPage *pNext; /* Next page in the fifo */ |
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234 i64 aSlot[1]; /* One or more slots for rowid values */ |
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235 }; |
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236 |
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237 /* |
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238 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation |
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239 ** of that structure is private to this file. |
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240 ** |
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241 ** The Fifo structure describes the entire fifo. |
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242 */ |
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243 typedef struct Fifo Fifo; |
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244 struct Fifo { |
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245 int nEntry; /* Total number of entries */ |
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246 sqlite3 *db; /* The associated database connection */ |
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247 FifoPage *pFirst; /* First page on the list */ |
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248 FifoPage *pLast; /* Last page on the list */ |
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249 }; |
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250 |
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251 /* |
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252 ** A Context stores the last insert rowid, the last statement change count, |
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253 ** and the current statement change count (i.e. changes since last statement). |
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254 ** The current keylist is also stored in the context. |
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255 ** Elements of Context structure type make up the ContextStack, which is |
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256 ** updated by the ContextPush and ContextPop opcodes (used by triggers). |
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257 ** The context is pushed before executing a trigger a popped when the |
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258 ** trigger finishes. |
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259 */ |
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260 typedef struct Context Context; |
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261 struct Context { |
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262 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ |
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263 int nChange; /* Statement changes (Vdbe.nChanges) */ |
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264 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ |
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265 }; |
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266 |
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267 /* |
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268 ** An instance of the virtual machine. This structure contains the complete |
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269 ** state of the virtual machine. |
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270 ** |
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271 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() |
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272 ** is really a pointer to an instance of this structure. |
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273 ** |
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274 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of |
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275 ** any virtual table method invocations made by the vdbe program. It is |
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276 ** set to 2 for xDestroy method calls and 1 for all other methods. This |
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277 ** variable is used for two purposes: to allow xDestroy methods to execute |
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278 ** "DROP TABLE" statements and to prevent some nasty side effects of |
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279 ** malloc failure when SQLite is invoked recursively by a virtual table |
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280 ** method function. |
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281 */ |
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282 struct Vdbe { |
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283 sqlite3 *db; /* The whole database */ |
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284 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ |
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285 int nOp; /* Number of instructions in the program */ |
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286 int nOpAlloc; /* Number of slots allocated for aOp[] */ |
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287 Op *aOp; /* Space to hold the virtual machine's program */ |
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288 int nLabel; /* Number of labels used */ |
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289 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ |
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290 int *aLabel; /* Space to hold the labels */ |
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291 Mem **apArg; /* Arguments to currently executing user function */ |
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292 Mem *aColName; /* Column names to return */ |
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293 int nCursor; /* Number of slots in apCsr[] */ |
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294 Cursor **apCsr; /* One element of this array for each open cursor */ |
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295 int nVar; /* Number of entries in aVar[] */ |
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296 Mem *aVar; /* Values for the OP_Variable opcode. */ |
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297 char **azVar; /* Name of variables */ |
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298 int okVar; /* True if azVar[] has been initialized */ |
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299 int magic; /* Magic number for sanity checking */ |
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300 int nMem; /* Number of memory locations currently allocated */ |
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301 Mem *aMem; /* The memory locations */ |
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302 int nCallback; /* Number of callbacks invoked so far */ |
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303 int cacheCtr; /* Cursor row cache generation counter */ |
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304 Fifo sFifo; /* A list of ROWIDs */ |
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305 int contextStackTop; /* Index of top element in the context stack */ |
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306 int contextStackDepth; /* The size of the "context" stack */ |
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307 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ |
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308 int pc; /* The program counter */ |
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309 int rc; /* Value to return */ |
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310 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ |
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311 int errorAction; /* Recovery action to do in case of an error */ |
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312 int inTempTrans; /* True if temp database is transactioned */ |
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313 int nResColumn; /* Number of columns in one row of the result set */ |
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314 char **azResColumn; /* Values for one row of result */ |
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315 char *zErrMsg; /* Error message written here */ |
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316 Mem *pResultSet; /* Pointer to an array of results */ |
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317 u8 explain; /* True if EXPLAIN present on SQL command */ |
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318 u8 changeCntOn; /* True to update the change-counter */ |
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319 u8 expired; /* True if the VM needs to be recompiled */ |
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320 u8 minWriteFileFormat; /* Minimum file format for writable database files */ |
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321 u8 inVtabMethod; /* See comments above */ |
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322 int nChange; /* Number of db changes made since last reset */ |
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323 i64 startTime; /* Time when query started - used for profiling */ |
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324 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ |
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325 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ |
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326 int aCounter[2]; /* Counters used by sqlite3_stmt_status() */ |
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327 int nSql; /* Number of bytes in zSql */ |
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328 char *zSql; /* Text of the SQL statement that generated this */ |
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329 #ifdef SQLITE_DEBUG |
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330 FILE *trace; /* Write an execution trace here, if not NULL */ |
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331 #endif |
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332 int openedStatement; /* True if this VM has opened a statement journal */ |
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333 #ifdef SQLITE_SSE |
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334 int fetchId; /* Statement number used by sqlite3_fetch_statement */ |
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335 int lru; /* Counter used for LRU cache replacement */ |
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336 #endif |
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337 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT |
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338 Vdbe *pLruPrev; |
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339 Vdbe *pLruNext; |
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340 #endif |
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341 }; |
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342 |
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343 /* |
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344 ** The following are allowed values for Vdbe.magic |
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345 */ |
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346 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ |
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347 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ |
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348 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ |
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349 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ |
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350 |
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351 /* |
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352 ** Function prototypes |
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353 */ |
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354 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); |
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355 void sqliteVdbePopStack(Vdbe*,int); |
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356 int sqlite3VdbeCursorMoveto(Cursor*); |
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357 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) |
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358 void sqlite3VdbePrintOp(FILE*, int, Op*); |
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359 #endif |
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360 int sqlite3VdbeSerialTypeLen(u32); |
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361 u32 sqlite3VdbeSerialType(Mem*, int); |
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362 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); |
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363 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); |
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364 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); |
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365 |
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366 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); |
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367 int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord*,int*); |
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368 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); |
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369 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); |
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370 int sqlite3VdbeExec(Vdbe*); |
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371 int sqlite3VdbeList(Vdbe*); |
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372 int sqlite3VdbeHalt(Vdbe*); |
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373 int sqlite3VdbeChangeEncoding(Mem *, int); |
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374 int sqlite3VdbeMemTooBig(Mem*); |
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375 int sqlite3VdbeMemCopy(Mem*, const Mem*); |
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376 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); |
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377 void sqlite3VdbeMemMove(Mem*, Mem*); |
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378 int sqlite3VdbeMemNulTerminate(Mem*); |
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379 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); |
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380 void sqlite3VdbeMemSetInt64(Mem*, i64); |
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381 void sqlite3VdbeMemSetDouble(Mem*, double); |
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382 void sqlite3VdbeMemSetNull(Mem*); |
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383 void sqlite3VdbeMemSetZeroBlob(Mem*,int); |
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384 int sqlite3VdbeMemMakeWriteable(Mem*); |
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385 int sqlite3VdbeMemStringify(Mem*, int); |
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386 i64 sqlite3VdbeIntValue(Mem*); |
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387 int sqlite3VdbeMemIntegerify(Mem*); |
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388 double sqlite3VdbeRealValue(Mem*); |
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389 void sqlite3VdbeIntegerAffinity(Mem*); |
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390 int sqlite3VdbeMemRealify(Mem*); |
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391 int sqlite3VdbeMemNumerify(Mem*); |
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392 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); |
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393 void sqlite3VdbeMemRelease(Mem *p); |
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394 void sqlite3VdbeMemReleaseExternal(Mem *p); |
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395 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); |
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396 const char *sqlite3OpcodeName(int); |
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397 int sqlite3VdbeOpcodeHasProperty(int, int); |
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398 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); |
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399 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT |
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400 int sqlite3VdbeReleaseBuffers(Vdbe *p); |
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401 #endif |
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402 |
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403 #ifndef NDEBUG |
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404 void sqlite3VdbeMemSanity(Mem*); |
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405 #endif |
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406 int sqlite3VdbeMemTranslate(Mem*, u8); |
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407 #ifdef SQLITE_DEBUG |
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408 void sqlite3VdbePrintSql(Vdbe*); |
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409 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); |
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410 #endif |
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411 int sqlite3VdbeMemHandleBom(Mem *pMem); |
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412 void sqlite3VdbeFifoInit(Fifo*, sqlite3*); |
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413 int sqlite3VdbeFifoPush(Fifo*, i64); |
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414 int sqlite3VdbeFifoPop(Fifo*, i64*); |
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415 void sqlite3VdbeFifoClear(Fifo*); |
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416 |
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417 #ifndef SQLITE_OMIT_INCRBLOB |
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418 int sqlite3VdbeMemExpandBlob(Mem *); |
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419 #else |
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420 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK |
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421 #endif |
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422 |
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423 #endif /* !defined(_VDBEINT_H_) */ |