main.c

一个小型的嵌入式数据库

    return SQLITE_BUSY;
  }
  assert( !sqlite3SafetyCheck(db) );

  /* FIX ME: db->magic may be set to SQLITE_MAGIC_CLOSED if the database
  ** cannot be opened for some reason. So this routine needs to run in
  ** that case. But maybe there should be an extra magic value for the
  ** "failed to open" state.
  */
  if( db->magic!=SQLITE_MAGIC_CLOSED && sqlite3SafetyOn(db) ){
    /* printf("DID NOT CLOSE\n"); fflush(stdout); */
    return SQLITE_ERROR;
  }

  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
    }
  }
  sqlite3ResetInternalSchema(db, 0);
  assert( db->nDb<=2 );
  assert( db->aDb==db->aDbStatic );
  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
    FuncDef *pFunc, *pNext;
    for(pFunc = (FuncDef*)sqliteHashData(i); pFunc; pFunc=pNext){
      pNext = pFunc->pNext;
      sqliteFree(pFunc);
    }
  }

  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
    sqliteFree(pColl);
  }
  sqlite3HashClear(&db->aCollSeq);

  sqlite3HashClear(&db->aFunc);
  sqlite3Error(db, SQLITE_OK, 0); /* Deallocates any cached error strings. */
  if( db->pValue ){
    sqlite3ValueFree(db->pValue);
  }
  if( db->pErr ){
    sqlite3ValueFree(db->pErr);
  }

  db->magic = SQLITE_MAGIC_ERROR;
  sqliteFree(db);
  return SQLITE_OK;
}

/*
** Rollback all database files.
*/
void sqlite3RollbackAll(sqlite3 *db){
  int i;
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].pBt ){
      sqlite3BtreeRollback(db->aDb[i].pBt);
      db->aDb[i].inTrans = 0;
    }
  }
  sqlite3ResetInternalSchema(db, 0);
}

/*
** Return a static string that describes the kind of error specified in the
** argument.
*/
const char *sqlite3ErrStr(int rc){
  const char *z;
  switch( rc ){
    case SQLITE_ROW:
    case SQLITE_DONE:
    case SQLITE_OK:         z = "not an error";                          break;
    case SQLITE_ERROR:      z = "SQL logic error or missing database";   break;
    case SQLITE_INTERNAL:   z = "internal SQLite implementation flaw";   break;
    case SQLITE_PERM:       z = "access permission denied";              break;
    case SQLITE_ABORT:      z = "callback requested query abort";        break;
    case SQLITE_BUSY:       z = "database is locked";                    break;
    case SQLITE_LOCKED:     z = "database table is locked";              break;
    case SQLITE_NOMEM:      z = "out of memory";                         break;
    case SQLITE_READONLY:   z = "attempt to write a readonly database";  break;
    case SQLITE_INTERRUPT:  z = "interrupted";                           break;
    case SQLITE_IOERR:      z = "disk I/O error";                        break;
    case SQLITE_CORRUPT:    z = "database disk image is malformed";      break;
    case SQLITE_NOTFOUND:   z = "table or record not found";             break;
    case SQLITE_FULL:       z = "database is full";                      break;
    case SQLITE_CANTOPEN:   z = "unable to open database file";          break;
    case SQLITE_PROTOCOL:   z = "database locking protocol failure";     break;
    case SQLITE_EMPTY:      z = "table contains no data";                break;
    case SQLITE_SCHEMA:     z = "database schema has changed";           break;
    case SQLITE_TOOBIG:     z = "too much data for one table row";       break;
    case SQLITE_CONSTRAINT: z = "constraint failed";                     break;
    case SQLITE_MISMATCH:   z = "datatype mismatch";                     break;
    case SQLITE_MISUSE:     z = "library routine called out of sequence";break;
    case SQLITE_NOLFS:      z = "kernel lacks large file support";       break;
    case SQLITE_AUTH:       z = "authorization denied";                  break;
    case SQLITE_FORMAT:     z = "auxiliary database format error";       break;
    case SQLITE_RANGE:      z = "bind or column index out of range";     break;
    case SQLITE_NOTADB:     z = "file is encrypted or is not a database";break;
    default:                z = "unknown error";                         break;
  }
  return z;
}

/*
** This routine implements a busy callback that sleeps and tries
** again until a timeout value is reached.  The timeout value is
** an integer number of milliseconds passed in as the first
** argument.
*/
static int sqliteDefaultBusyCallback(
 void *Timeout,           /* Maximum amount of time to wait */
 int count                /* Number of times table has been busy */
){
#if SQLITE_MIN_SLEEP_MS==1
  static const char delays[] =
     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50,  50, 100};
  static const short int totals[] =
     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228, 287};
# define NDELAY (sizeof(delays)/sizeof(delays[0]))
  ptr timeout = (ptr)Timeout;
  ptr delay, prior;

  if( count <= NDELAY ){
    delay = delays[count-1];
    prior = totals[count-1];
  }else{
    delay = delays[NDELAY-1];
    prior = totals[NDELAY-1] + delay*(count-NDELAY-1);
  }
  if( prior + delay > timeout ){
    delay = timeout - prior;
    if( delay<=0 ) return 0;
  }
  sqlite3OsSleep(delay);
  return 1;
#else
  int timeout = (int)Timeout;
  if( (count+1)*1000 > timeout ){
    return 0;
  }
  sqlite3OsSleep(1000);
  return 1;
#endif
}

/*
** This routine sets the busy callback for an Sqlite database to the
** given callback function with the given argument.
*/
int sqlite3_busy_handler(
  sqlite3 *db,
  int (*xBusy)(void*,int),
  void *pArg
){
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  db->busyHandler.xFunc = xBusy;
  db->busyHandler.pArg = pArg;
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/*
** This routine sets the progress callback for an Sqlite database to the
** given callback function with the given argument. The progress callback will
** be invoked every nOps opcodes.
*/
void sqlite3_progress_handler(
  sqlite3 *db, 
  int nOps,
  int (*xProgress)(void*), 
  void *pArg
){
  if( !sqlite3SafetyCheck(db) ){
    if( nOps>0 ){
      db->xProgress = xProgress;
      db->nProgressOps = nOps;
      db->pProgressArg = pArg;
    }else{
      db->xProgress = 0;
      db->nProgressOps = 0;
      db->pProgressArg = 0;
    }
  }
}
#endif


/*
** This routine installs a default busy handler that waits for the
** specified number of milliseconds before returning 0.
*/
int sqlite3_busy_timeout(sqlite3 *db, int ms){
  if( ms>0 ){
    sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)(ptr)ms);
  }else{
    sqlite3_busy_handler(db, 0, 0);
  }
  return SQLITE_OK;
}

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite3_interrupt(sqlite3 *db){
  if( !sqlite3SafetyCheck(db) ){
    db->flags |= SQLITE_Interrupt;
  }
}

/*
** Windows systems should call this routine to free memory that
** is returned in the in the errmsg parameter of sqlite3_open() when
** SQLite is a DLL.  For some reason, it does not work to call free()
** directly.
**
** Note that we need to call free() not sqliteFree() here.
*/
void sqlite3_free(char *p){ free(p); }

/*
** Create new user functions.
*/
int sqlite3_create_function(
  sqlite3 *db,
  const char *zFunctionName,
  int nArg,
  int enc,
  void *pUserData,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
  void (*xFinal)(sqlite3_context*)
){
  FuncDef *p;
  int nName;

  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  if( zFunctionName==0 ||
      (xFunc && (xFinal || xStep)) || 
      (!xFunc && (xFinal && !xStep)) ||
      (!xFunc && (!xFinal && xStep)) ||
      (nArg<-1 || nArg>127) ||
      (255<(nName = strlen(zFunctionName))) ){
    return SQLITE_ERROR;
  }
  
#ifndef SQLITE_OMIT_UTF16
  /* 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 SQLITE_ANY is specified, add three versions of the function
  ** to the hash table.
  */
  if( enc==SQLITE_UTF16 ){
    enc = SQLITE_UTF16NATIVE;
  }else if( enc==SQLITE_ANY ){
    int rc;
    rc = sqlite3_create_function(db, zFunctionName, nArg, SQLITE_UTF8,
         pUserData, xFunc, xStep, xFinal);
    if( rc!=SQLITE_OK ) return rc;
    rc = sqlite3_create_function(db, zFunctionName, nArg, SQLITE_UTF16LE,
        pUserData, xFunc, xStep, xFinal);
    if( rc!=SQLITE_OK ) return rc;
    enc = SQLITE_UTF16BE;
  }
#else
  enc = SQLITE_UTF8;
#endif
  
  /* Check if an existing function is being overridden or deleted. If so,
  ** and there are active VMs, then return SQLITE_BUSY. If a function
  ** is being overridden/deleted but there are no active VMs, allow the
  ** operation to continue but invalidate all precompiled statements.
  */
  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 0);
  if( p && p->iPrefEnc==enc && p->nArg==nArg ){
    if( db->activeVdbeCnt ){
      sqlite3Error(db, SQLITE_BUSY, 
        "Unable to delete/modify user-function due to active statements");
      return SQLITE_BUSY;
    }else{
      sqlite3ExpirePreparedStatements(db);
    }
  }

  p = sqlite3FindFunction(db, zFunctionName, nName, nArg, enc, 1);
  if( p==0 ) return SQLITE_NOMEM;
  p->xFunc = xFunc;
  p->xStep = xStep;
  p->xFinalize = xFinal;
  p->pUserData = pUserData;
  return SQLITE_OK;
}
#ifndef SQLITE_OMIT_UTF16
int sqlite3_create_function16(
  sqlite3 *db,
  const void *zFunctionName,
  int nArg,
  int eTextRep,
  void *pUserData,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  void (*xFinal)(sqlite3_context*)
){
  int rc;
  char const *zFunc8;
  sqlite3_value *pTmp;

  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  pTmp = sqlite3GetTransientValue(db);
  sqlite3ValueSetStr(pTmp, -1, zFunctionName, SQLITE_UTF16NATIVE,SQLITE_STATIC);
  zFunc8 = sqlite3ValueText(pTmp, SQLITE_UTF8);

  if( !zFunc8 ){
    return SQLITE_NOMEM;
  }
  rc = sqlite3_create_function(db, zFunc8, nArg, eTextRep, 
      pUserData, xFunc, xStep, xFinal);
  return rc;
}
#endif

/*
** Register a trace function.  The pArg from the previously registered trace
** is returned.  
**
** A NULL trace function means that no tracing is executes.  A non-NULL
** trace is a pointer to a function that is invoked at the start of each
** sqlite3_exec().
*/
void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
  void *pOld = db->pTraceArg;
  db->xTrace = xTrace;
  db->pTraceArg = pArg;
  return pOld;
}

/*** EXPERIMENTAL ***
**
** Register a function to be invoked when a transaction comments.
** If either function returns non-zero, then the commit becomes a
** rollback.
*/
void *sqlite3_commit_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  int (*xCallback)(void*),  /* Function to invoke on each commit */
  void *pArg                /* Argument to the function */
){
  void *pOld = db->pCommitArg;
  db->xCommitCallback = xCallback;
  db->pCommitArg = pArg;
  return pOld;
}


/*
** This routine is called to create a connection to a database BTree
** driver.  If zFilename is the name of a file, then that file is
** opened and used.  If zFilename is the magic name ":memory:" then
** the database is stored in memory (and is thus forgotten as soon as
** the connection is closed.)  If zFilename is NULL then the database
** is for temporary use only and is deleted as soon as the connection
** is closed.
**
** A temporary database can be either a disk file (that is automatically
** deleted when the file is closed) or a set of red-black trees held in memory,
** depending on the values of the TEMP_STORE compile-time macro and the
** db->temp_store variable, according to the following chart:
**
**       TEMP_STORE     db->temp_store     Location of temporary database
**       ----------     --------------     ------------------------------
**           0               any             file
**           1                1              file
**           1                2              memory
**           1                0              file
**           2                1              file
**           2                2              memory
**           2                0              memory
**           3               any             memory
*/
int sqlite3BtreeFactory(
  const sqlite3 *db,        /* Main database when opening aux otherwise 0 */
  const char *zFilename,    /* Name of the file containing the BTree database */
  int omitJournal,          /* if TRUE then do not journal this file */
  int nCache,               /* How many pages in the page cache */
  Btree **ppBtree           /* Pointer to new Btree object written here */
){
  int btree_flags = 0;
  int rc;
  
  assert( ppBtree != 0);
  if( omitJournal ){
    btree_flags |= BTREE_OMIT_JOURNAL;
  }
  if( db->flags & SQLITE_NoReadlock ){
    btree_flags |= BTREE_NO_READLOCK;
  }
  if( zFilename==0 ){
#if TEMP_STORE==0
    /* Do nothing */
#endif
#ifndef SQLITE_OMIT_MEMORYDB
#if TEMP_STORE==1
    if( db->temp_store==2 ) zFilename = ":memory:";
#endif
#if TEMP_STORE==2
    if( db->temp_store!=1 ) zFilename = ":memory:";
#endif
#if TEMP_STORE==3
    zFilename = ":memory:";
#endif
#endif /* SQLITE_OMIT_MEMORYDB */
  }

  rc = sqlite3BtreeOpen(zFilename, ppBtree, btree_flags);
  if( rc==SQLITE_OK ){
    sqlite3BtreeSetBusyHandler(*ppBtree, (void*)&db->busyHandler);
    sqlite3BtreeSetCacheSize(*ppBtree, nCache);
  }
  return rc;
}

/*
** Return UTF-8 encoded English language explanation of the most recent
** error.
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( sqlite3_malloc_failed ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }
  z = sqlite3_value_text(db->pErr);
  if( z==0 ){
    z = sqlite3ErrStr(db->errCode);
  }
  return z;
}

#ifndef SQLITE_OMIT_UTF16
/*
** Return UTF-16 encoded English language explanation of the most recent
** error.
*/
const void *sqlite3_errmsg16(sqlite3 *db){
  /* Because all the characters in the string are in the unicode
  ** range 0x00-0xFF, if we pad the big-endian string with a 
  ** zero byte, we can obtain the little-endian string with
  ** &big_endian[1].
  */
  static const char outOfMemBe[] = {
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 'm', 0, 'e', 0, 'm', 0, 'o', 0, 'r', 0, 'y', 0, 0, 0
  };