build.c

一个小型的嵌入式数据库

void sqlite3AddColumn(Parse *pParse, Token *pName){
  Table *p;
  int i;
  char *z;
  Column *pCol;
  if( (p = pParse->pNewTable)==0 ) return;
  z = sqlite3NameFromToken(pName);
  if( z==0 ) return;
  for(i=0; i<p->nCol; i++){
    if( STRICMP(z, p->aCol[i].zName) ){
      sqlite3ErrorMsg(pParse, "duplicate column name: %s", z);
      sqliteFree(z);
      return;
    }
  }
  if( (p->nCol & 0x7)==0 ){
    Column *aNew;
    aNew = sqliteRealloc( p->aCol, (p->nCol+8)*sizeof(p->aCol[0]));
    if( aNew==0 ) return;
    p->aCol = aNew;
  }
  pCol = &p->aCol[p->nCol];
  memset(pCol, 0, sizeof(p->aCol[0]));
  pCol->zName = z;
 
  /* If there is no type specified, columns have the default affinity
  ** 'NONE'. If there is a type specified, then sqlite3AddColumnType() will
  ** be called next to set pCol->affinity correctly.
  */
  pCol->affinity = SQLITE_AFF_NONE;
  pCol->pColl = pParse->db->pDfltColl;
  p->nCol++;
}

/*
** This routine is called by the parser while in the middle of
** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
** been seen on a column.  This routine sets the notNull flag on
** the column currently under construction.
*/
void sqlite3AddNotNull(Parse *pParse, int onError){
  Table *p;
  int i;
  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;
  if( i>=0 ) p->aCol[i].notNull = onError;
}

/*
** Scan the column type name zType (length nType) and return the
** associated affinity type.
**
** This routine does a case-independent search of zType for the 
** substrings in the following table. If one of the substrings is
** found, the corresponding affinity is returned. If zType contains
** more than one of the substrings, entries toward the top of 
** the table take priority. For example, if zType is 'BLOBINT', 
** SQLITE_AFF_INTEGER is returned.
**
** Substring     | Affinity
** --------------------------------
** 'INT'         | SQLITE_AFF_INTEGER
** 'CHAR'        | SQLITE_AFF_TEXT
** 'CLOB'        | SQLITE_AFF_TEXT
** 'TEXT'        | SQLITE_AFF_TEXT
** 'BLOB'        | SQLITE_AFF_NONE
**
** If none of the substrings in the above table are found,
** SQLITE_AFF_NUMERIC is returned.
*/
static char sqlite3AffinityType(const char *zType, int nType){
  u32 h = 0;
  char aff = SQLITE_AFF_NUMERIC;
  const unsigned char *zIn = zType;
  const unsigned char *zEnd = (zIn+nType);

  while( zIn!=zEnd ){
    h = (h<<8) + sqlite3UpperToLower[*zIn];
    zIn++;
    if( h==(('c'<<24)+('h'<<16)+('a'<<8)+'r') ){             /* CHAR */
      aff = SQLITE_AFF_TEXT; 
    }else if( h==(('c'<<24)+('l'<<16)+('o'<<8)+'b') ){       /* CLOB */
      aff = SQLITE_AFF_TEXT;
    }else if( h==(('t'<<24)+('e'<<16)+('x'<<8)+'t') ){       /* TEXT */
      aff = SQLITE_AFF_TEXT;
    }else if( h==(('b'<<24)+('l'<<16)+('o'<<8)+'b')          /* BLOB */
        && aff==SQLITE_AFF_NUMERIC ){
      aff = SQLITE_AFF_NONE;
    }else if( (h&0x00FFFFFF)==(('i'<<16)+('n'<<8)+'t') ){    /* INT */
      aff = SQLITE_AFF_INTEGER; 
      break;
    }
  }

  return aff;
}

/*
** This routine is called by the parser while in the middle of
** parsing a CREATE TABLE statement.  The pFirst token is the first
** token in the sequence of tokens that describe the type of the
** column currently under construction.   pLast is the last token
** in the sequence.  Use this information to construct a string
** that contains the typename of the column and store that string
** in zType.
*/ 
void sqlite3AddColumnType(Parse *pParse, Token *pFirst, Token *pLast){
  Table *p;
  int i, j;
  int n;
  char *z;
  const unsigned char *zIn;

  Column *pCol;
  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;
  if( i<0 ) return;
  pCol = &p->aCol[i];
  zIn = pFirst->z;
  n = pLast->n + (pLast->z - zIn);
  assert( pCol->zType==0 );
  z = pCol->zType = sqliteMallocRaw(n+1);
  if( z==0 ) return;
  for(i=j=0; i<n; i++){
    int c = zIn[i];
    if( isspace(c) ) continue;
    z[j++] = c;
  }
  z[j] = 0;
  pCol->affinity = sqlite3AffinityType(z, n);
}

/*
** The expression is the default value for the most recently added column
** of the table currently under construction.
**
** Default value expressions must be constant.  Raise an exception if this
** is not the case.
**
** This routine is called by the parser while in the middle of
** parsing a CREATE TABLE statement.
*/
void sqlite3AddDefaultValue(Parse *pParse, Expr *pExpr){
  Table *p;
  Column *pCol;
  if( (p = pParse->pNewTable)==0 ) return;
  pCol = &(p->aCol[p->nCol-1]);
  if( !sqlite3ExprIsConstant(pExpr) ){
    sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
        pCol->zName);
  }else{
    sqlite3ExprDelete(pCol->pDflt);
    pCol->pDflt = sqlite3ExprDup(pExpr);
  }
  sqlite3ExprDelete(pExpr);
}

/*
** Designate the PRIMARY KEY for the table.  pList is a list of names 
** of columns that form the primary key.  If pList is NULL, then the
** most recently added column of the table is the primary key.
**
** A table can have at most one primary key.  If the table already has
** a primary key (and this is the second primary key) then create an
** error.
**
** If the PRIMARY KEY is on a single column whose datatype is INTEGER,
** then we will try to use that column as the rowid.  Set the Table.iPKey
** field of the table under construction to be the index of the
** INTEGER PRIMARY KEY column.  Table.iPKey is set to -1 if there is
** no INTEGER PRIMARY KEY.
**
** If the key is not an INTEGER PRIMARY KEY, then create a unique
** index for the key.  No index is created for INTEGER PRIMARY KEYs.
*/
void sqlite3AddPrimaryKey(
  Parse *pParse,    /* Parsing context */
  ExprList *pList,  /* List of field names to be indexed */
  int onError,      /* What to do with a uniqueness conflict */
  int autoInc       /* True if the AUTOINCREMENT keyword is present */
){
  Table *pTab = pParse->pNewTable;
  char *zType = 0;
  int iCol = -1, i;
  if( pTab==0 ) goto primary_key_exit;
  if( pTab->hasPrimKey ){
    sqlite3ErrorMsg(pParse, 
      "table \"%s\" has more than one primary key", pTab->zName);
    goto primary_key_exit;
  }
  pTab->hasPrimKey = 1;
  if( pList==0 ){
    iCol = pTab->nCol - 1;
    pTab->aCol[iCol].isPrimKey = 1;
  }else{
    for(i=0; i<pList->nExpr; i++){
      for(iCol=0; iCol<pTab->nCol; iCol++){
        if( sqlite3StrICmp(pList->a[i].zName, pTab->aCol[iCol].zName)==0 ){
          break;
        }
      }
      if( iCol<pTab->nCol ) pTab->aCol[iCol].isPrimKey = 1;
    }
    if( pList->nExpr>1 ) iCol = -1;
  }
  if( iCol>=0 && iCol<pTab->nCol ){
    zType = pTab->aCol[iCol].zType;
  }
  if( zType && sqlite3StrICmp(zType, "INTEGER")==0 ){
    pTab->iPKey = iCol;
    pTab->keyConf = onError;
    pTab->autoInc = autoInc;
  }else if( autoInc ){
#ifndef SQLITE_OMIT_AUTOINCREMENT
    sqlite3ErrorMsg(pParse, "AUTOINCREMENT is only allowed on an "
       "INTEGER PRIMARY KEY");
#endif
  }else{
    sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0, 0);
    pList = 0;
  }

primary_key_exit:
  sqlite3ExprListDelete(pList);
  return;
}

/*
** Set the collation function of the most recently parsed table column
** to the CollSeq given.
*/
void sqlite3AddCollateType(Parse *pParse, const char *zType, int nType){
  Table *p;
  Index *pIdx;
  CollSeq *pColl;
  int i;

  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;

  pColl = sqlite3LocateCollSeq(pParse, zType, nType);
  p->aCol[i].pColl = pColl;

  /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
  ** then an index may have been created on this column before the
  ** collation type was added. Correct this if it is the case.
  */
  for(pIdx = p->pIndex; pIdx; pIdx=pIdx->pNext){
    assert( pIdx->nColumn==1 );
    if( pIdx->aiColumn[0]==i ) pIdx->keyInfo.aColl[0] = pColl;
  }
}

/*
** Locate and return an entry from the db.aCollSeq hash table. If the entry
** specified by zName and nName is not found and parameter 'create' is
** true, then create a new entry. Otherwise return NULL.
**
** Each pointer stored in the sqlite3.aCollSeq hash table contains an
** array of three CollSeq structures. The first is the collation sequence
** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
**
** Stored immediately after the three collation sequences is a copy of
** the collation sequence name. A pointer to this string is stored in
** each collation sequence structure.
*/
static CollSeq * findCollSeqEntry(
  sqlite3 *db,
  const char *zName,
  int nName,
  int create
){
  CollSeq *pColl;
  if( nName<0 ) nName = strlen(zName);
  pColl = sqlite3HashFind(&db->aCollSeq, zName, nName);

  if( 0==pColl && create ){
    pColl = sqliteMalloc( 3*sizeof(*pColl) + nName + 1 );
    if( pColl ){
      pColl[0].zName = (char*)&pColl[3];
      pColl[0].enc = SQLITE_UTF8;
      pColl[1].zName = (char*)&pColl[3];
      pColl[1].enc = SQLITE_UTF16LE;
      pColl[2].zName = (char*)&pColl[3];
      pColl[2].enc = SQLITE_UTF16BE;
      memcpy(pColl[0].zName, zName, nName);
      pColl[0].zName[nName] = 0;
      sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);
    }
  }
  return pColl;
}

/*
** Parameter zName points to a UTF-8 encoded string nName bytes long.
** Return the CollSeq* pointer for the collation sequence named zName
** for the encoding 'enc' from the database 'db'.
**
** If the entry specified is not found and 'create' is true, then create a
** new entry.  Otherwise return NULL.
*/
CollSeq *sqlite3FindCollSeq(
  sqlite3 *db,
  u8 enc,
  const char *zName,
  int nName,
  int create
){
  CollSeq *pColl = findCollSeqEntry(db, zName, nName, create);
  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
  if( pColl ) pColl += enc-1;
  return pColl;
}

/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the database text encoding of name zName, length nName.
** If the collation sequence
*/
static void callCollNeeded(sqlite3 *db, const char *zName, int nName){
  assert( !db->xCollNeeded || !db->xCollNeeded16 );
  if( nName<0 ) nName = strlen(zName);
  if( db->xCollNeeded ){
    char *zExternal = sqliteStrNDup(zName, nName);
    if( !zExternal ) return;
    db->xCollNeeded(db->pCollNeededArg, db, (int)db->enc, zExternal);
    sqliteFree(zExternal);
  }
#ifndef SQLITE_OMIT_UTF16
  if( db->xCollNeeded16 ){
    char const *zExternal;
    sqlite3_value *pTmp = sqlite3GetTransientValue(db);
    sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
    zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
    if( !zExternal ) return;
    db->xCollNeeded16(db->pCollNeededArg, db, (int)db->enc, zExternal);
  }
#endif
}

/*
** This routine is called if the collation factory fails to deliver a
** collation function in the best encoding but there may be other versions
** of this collation function (for other text encodings) available. Use one
** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
** possible.
*/
static int synthCollSeq(Parse *pParse, CollSeq *pColl){
  CollSeq *pColl2;
  char *z = pColl->zName;
  int n = strlen(z);
  sqlite3 *db = pParse->db;
  int i;
  static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
  for(i=0; i<3; i++){
    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, n, 0);
    if( pColl2->xCmp!=0 ){
      memcpy(pColl, pColl2, sizeof(CollSeq));
      return SQLITE_OK;
    }
  }
  if( pParse->nErr==0 ){
    sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", n, z);
  }
  pParse->nErr++;
  return SQLITE_ERROR;
}

/*
** This routine is called on a collation sequence before it is used to
** check that it is defined. An undefined collation sequence exists when
** a database is loaded that contains references to collation sequences
** that have not been defined by sqlite3_create_collation() etc.
**
** If required, this routine calls the 'collation needed' callback to
** request a definition of the collating sequence. If this doesn't work, 
** an equivalent collating sequence that uses a text encoding different
** from the main database is substituted, if one is available.
*/
int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
  if( pColl && !pColl->xCmp ){
    /* No collation sequence of this type for this encoding is registered.
    ** Call the collation factory to see if it can supply us with one.
    */
    callCollNeeded(pParse->db, pColl->zName, strlen(pColl->zName));
    if( !pColl->xCmp && synthCollSeq(pParse, pColl) ){
      return SQLITE_ERROR;
    }
  }
  return SQLITE_OK;
}

/*
** Call sqlite3CheckCollSeq() for all collating sequences in an index,
** in order to verify that all the necessary collating sequences are
** loaded.
*/
int sqlite3CheckIndexCollSeq(Parse *pParse, Index *pIdx){
  if( pIdx ){
    int i;
    for(i=0; i<pIdx->nColumn; i++){
      if( sqlite3CheckCollSeq(pParse, pIdx->keyInfo.aColl[i]) ){
        return SQLITE_ERROR;
      }
    }
  }
  return SQLITE_OK;
}