main.c

一个小型的嵌入式数据库

  static const char misuseBe [] = {
    0, 'l', 0, 'i', 0, 'b', 0, 'r', 0, 'a', 0, 'r', 0, 'y', 0, ' ', 
    0, 'r', 0, 'o', 0, 'u', 0, 't', 0, 'i', 0, 'n', 0, 'e', 0, ' ', 
    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
  };

  const void *z;
  if( sqlite3_malloc_failed ){
    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  z = sqlite3_value_text16(db->pErr);
  if( z==0 ){
    sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
         SQLITE_UTF8, SQLITE_STATIC);
    z = sqlite3_value_text16(db->pErr);
  }
  return z;
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** Return the most recent error code generated by an SQLite routine.
*/
int sqlite3_errcode(sqlite3 *db){
  if( sqlite3_malloc_failed ){
    return SQLITE_NOMEM;
  }
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  return db->errCode;
}

/*
** Check schema cookies in all databases.  If any cookie is out
** of date, return 0.  If all schema cookies are current, return 1.
*/
static int schemaIsValid(sqlite3 *db){
  int iDb;
  int rc;
  BtCursor *curTemp;
  int cookie;
  int allOk = 1;

  for(iDb=0; allOk && iDb<db->nDb; iDb++){
    Btree *pBt;
    pBt = db->aDb[iDb].pBt;
    if( pBt==0 ) continue;
    rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, 0, &curTemp);
    if( rc==SQLITE_OK ){
      rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
      if( rc==SQLITE_OK && cookie!=db->aDb[iDb].schema_cookie ){
        allOk = 0;
      }
      sqlite3BtreeCloseCursor(curTemp);
    }
  }
  return allOk;
}

/*
** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
*/
int sqlite3_prepare(
  sqlite3 *db,              /* Database handle. */
  const char *zSql,         /* UTF-8 encoded SQL statement. */
  int nBytes,               /* Length of zSql in bytes. */
  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
  const char** pzTail       /* OUT: End of parsed string */
){
  Parse sParse;
  char *zErrMsg = 0;
  int rc = SQLITE_OK;

  if( sqlite3_malloc_failed ){
    return SQLITE_NOMEM;
  }

  assert( ppStmt );
  *ppStmt = 0;
  if( sqlite3SafetyOn(db) ){
    return SQLITE_MISUSE;
  }

  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sqlite3RunParser(&sParse, zSql, &zErrMsg);

  if( sqlite3_malloc_failed ){
    rc = SQLITE_NOMEM;
    sqlite3RollbackAll(db);
    sqlite3ResetInternalSchema(db, 0);
    db->flags &= ~SQLITE_InTrans;
    goto prepare_out;
  }
  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
  if( sParse.rc!=SQLITE_OK && sParse.checkSchema && !schemaIsValid(db) ){
    sParse.rc = SQLITE_SCHEMA;
  }
  if( sParse.rc==SQLITE_SCHEMA ){
    sqlite3ResetInternalSchema(db, 0);
  }
  if( pzTail ) *pzTail = sParse.zTail;
  rc = sParse.rc;

#ifndef SQLITE_OMIT_EXPLAIN
  if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
    sqlite3VdbeSetNumCols(sParse.pVdbe, 5);
    sqlite3VdbeSetColName(sParse.pVdbe, 0, "addr", P3_STATIC);
    sqlite3VdbeSetColName(sParse.pVdbe, 1, "opcode", P3_STATIC);
    sqlite3VdbeSetColName(sParse.pVdbe, 2, "p1", P3_STATIC);
    sqlite3VdbeSetColName(sParse.pVdbe, 3, "p2", P3_STATIC);
    sqlite3VdbeSetColName(sParse.pVdbe, 4, "p3", P3_STATIC);
  } 
#endif

prepare_out:
  if( sqlite3SafetyOff(db) ){
    rc = SQLITE_MISUSE;
  }
  if( rc==SQLITE_OK ){
    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
  }else if( sParse.pVdbe ){
    sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
  }

  if( zErrMsg ){
    sqlite3Error(db, rc, "%s", zErrMsg);
    sqliteFree(zErrMsg);
  }else{
    sqlite3Error(db, rc, 0);
  }
  return rc;
}

#ifndef SQLITE_OMIT_UTF16
/*
** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
*/
int sqlite3_prepare16(
  sqlite3 *db,              /* Database handle. */ 
  const void *zSql,         /* UTF-8 encoded SQL statement. */
  int nBytes,               /* Length of zSql in bytes. */
  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
  const void **pzTail       /* OUT: End of parsed string */
){
  /* This function currently works by first transforming the UTF-16
  ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
  ** tricky bit is figuring out the pointer to return in *pzTail.
  */
  char const *zSql8 = 0;
  char const *zTail8 = 0;
  int rc;
  sqlite3_value *pTmp;

  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  pTmp = sqlite3GetTransientValue(db);
  sqlite3ValueSetStr(pTmp, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zSql8 = sqlite3ValueText(pTmp, SQLITE_UTF8);
  if( !zSql8 ){
    sqlite3Error(db, SQLITE_NOMEM, 0);
    return SQLITE_NOMEM;
  }
  rc = sqlite3_prepare(db, zSql8, -1, ppStmt, &zTail8);

  if( zTail8 && pzTail ){
    /* If sqlite3_prepare returns a tail pointer, we calculate the
    ** equivalent pointer into the UTF-16 string by counting the unicode
    ** characters between zSql8 and zTail8, and then returning a pointer
    ** the same number of characters into the UTF-16 string.
    */
    int chars_parsed = sqlite3utf8CharLen(zSql8, zTail8-zSql8);
    *pzTail = (u8 *)zSql + sqlite3utf16ByteLen(zSql, chars_parsed);
  }
 
  return rc;
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** This routine does the work of opening a database on behalf of
** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"  
** is UTF-8 encoded. The fourth argument, "def_enc" is one of the TEXT_*
** macros from sqliteInt.h. If we end up creating a new database file
** (not opening an existing one), the text encoding of the database
** will be set to this value.
*/
static int openDatabase(
  const char *zFilename, /* Database filename UTF-8 encoded */
  sqlite3 **ppDb         /* OUT: Returned database handle */
){
  sqlite3 *db;
  int rc, i;

  /* Allocate the sqlite data structure */
  db = sqliteMalloc( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  db->nDb = 2;
  db->aDb = db->aDbStatic;
  db->enc = SQLITE_UTF8;
  db->autoCommit = 1;
  db->flags |= SQLITE_ShortColNames;
  sqlite3HashInit(&db->aFunc, SQLITE_HASH_STRING, 0);
  sqlite3HashInit(&db->aCollSeq, SQLITE_HASH_STRING, 0);
  for(i=0; i<db->nDb; i++){
    sqlite3HashInit(&db->aDb[i].tblHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].idxHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].trigHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&db->aDb[i].aFKey, SQLITE_HASH_STRING, 1);
  }
  
  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.
  */
  if( sqlite3_create_collation(db, "BINARY", SQLITE_UTF8, 0,binCollFunc) ||
      sqlite3_create_collation(db, "BINARY", SQLITE_UTF16, 0,binCollFunc) ||
      !(db->pDfltColl = sqlite3FindCollSeq(db, db->enc, "BINARY", 6, 0)) ){
    rc = db->errCode;
    assert( rc!=SQLITE_OK );
    db->magic = SQLITE_MAGIC_CLOSED;
    goto opendb_out;
  }

  /* Also add a UTF-8 case-insensitive collation sequence. */
  sqlite3_create_collation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc);

  /* Open the backend database driver */
  rc = sqlite3BtreeFactory(db, zFilename, 0, MAX_PAGES, &db->aDb[0].pBt);
  if( rc!=SQLITE_OK ){
    sqlite3Error(db, rc, 0);
    db->magic = SQLITE_MAGIC_CLOSED;
    goto opendb_out;
  }
  db->aDb[0].zName = "main";
  db->aDb[1].zName = "temp";

  /* The default safety_level for the main database is 'full' for the temp
  ** database it is 'NONE'. This matches the pager layer defaults.  */
  db->aDb[0].safety_level = 3;
  db->aDb[1].safety_level = 1;

  /* Register all built-in functions, but do not attempt to read the
  ** database schema yet. This is delayed until the first time the database
  ** is accessed.
  */
  sqlite3RegisterBuiltinFunctions(db);
  sqlite3Error(db, SQLITE_OK, 0);
  db->magic = SQLITE_MAGIC_OPEN;

opendb_out:
  if( sqlite3_errcode(db)==SQLITE_OK && sqlite3_malloc_failed ){
    sqlite3Error(db, SQLITE_NOMEM, 0);
  }
  *ppDb = db;
  return sqlite3_errcode(db);
}

/*
** Open a new database handle.
*/
int sqlite3_open(
  const char *zFilename, 
  sqlite3 **ppDb 
){
  return openDatabase(zFilename, ppDb);
}

#ifndef SQLITE_OMIT_UTF16
/*
** Open a new database handle.
*/
int sqlite3_open16(
  const void *zFilename, 
  sqlite3 **ppDb
){
  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
  int rc = SQLITE_NOMEM;
  sqlite3_value *pVal;

  assert( ppDb );
  *ppDb = 0;
  pVal = sqlite3ValueNew();
  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb);
    if( rc==SQLITE_OK && *ppDb ){
      sqlite3_exec(*ppDb, "PRAGMA encoding = 'UTF-16'", 0, 0, 0);
    }
  }
  if( pVal ){
    sqlite3ValueFree(pVal);
  }

  return rc;
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** The following routine destroys a virtual machine that is created by
** the sqlite3_compile() routine. The integer returned is an SQLITE_
** success/failure code that describes the result of executing the virtual
** machine.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
int sqlite3_finalize(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3VdbeFinalize((Vdbe*)pStmt);
  }
  return rc;
}

/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from
** the prior execution is returned.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3VdbeReset((Vdbe*)pStmt);
    sqlite3VdbeMakeReady((Vdbe*)pStmt, -1, 0, 0, 0, 0);
  }
  return rc;
}

/*
** Register a new collation sequence with the database handle db.
*/
int sqlite3_create_collation(
  sqlite3* db, 
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  CollSeq *pColl;
  int rc = SQLITE_OK;
  
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }

  /* If SQLITE_UTF16 is specified as the encoding type, transform this
  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
  */
  if( enc==SQLITE_UTF16 ){
    enc = SQLITE_UTF16NATIVE;
  }

  if( enc!=SQLITE_UTF8 && enc!=SQLITE_UTF16LE && enc!=SQLITE_UTF16BE ){
    sqlite3Error(db, SQLITE_ERROR, 
        "Param 3 to sqlite3_create_collation() must be one of "
        "SQLITE_UTF8, SQLITE_UTF16, SQLITE_UTF16LE or SQLITE_UTF16BE"
    );
    return SQLITE_ERROR;
  }

  /* Check if this call is removing or replacing an existing collation 
  ** sequence. If so, and there are active VMs, return busy. If there
  ** are no active VMs, invalidate any pre-compiled statements.
  */
  pColl = sqlite3FindCollSeq(db, (u8)enc, zName, strlen(zName), 0);
  if( pColl && pColl->xCmp ){
    if( db->activeVdbeCnt ){
      sqlite3Error(db, SQLITE_BUSY, 
        "Unable to delete/modify collation sequence due to active statements");
      return SQLITE_BUSY;
    }
    sqlite3ExpirePreparedStatements(db);
  }

  pColl = sqlite3FindCollSeq(db, (u8)enc, zName, strlen(zName), 1);
  if( 0==pColl ){
   rc = SQLITE_NOMEM;
  }else{
    pColl->xCmp = xCompare;
    pColl->pUser = pCtx;
    pColl->enc = enc;
  }
  sqlite3Error(db, rc, 0);
  return rc;
}

#ifndef SQLITE_OMIT_UTF16
/*
** Register a new collation sequence with the database handle db.
*/
int sqlite3_create_collation16(
  sqlite3* db, 
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  char const *zName8;
  sqlite3_value *pTmp;
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  pTmp = sqlite3GetTransientValue(db);
  sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zName8 = sqlite3ValueText(pTmp, SQLITE_UTF8);
  return sqlite3_create_collation(db, zName8, enc, pCtx, xCompare);
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** Register a collation sequence factory callback with the database handle
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
){
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  db->xCollNeeded = xCollNeeded;
  db->xCollNeeded16 = 0;
  db->pCollNeededArg = pCollNeededArg;
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_UTF16
/*
** Register a collation sequence factory callback with the database handle
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed16(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
){
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  db->xCollNeeded = 0;
  db->xCollNeeded16 = xCollNeeded16;
  db->pCollNeededArg = pCollNeededArg;
  return SQLITE_OK;
}
#endif /* SQLITE_OMIT_UTF16 */