test8.c

sqlite-3.4.1,嵌入式数据库.是一个功能强大的开源数据库,给学习和研发以及小型公司的发展带来了全所未有的好处.

/*
** 2006 June 10
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test8.c,v 1.48 2007/07/20 00:35:59 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE

typedef struct echo_vtab echo_vtab;
typedef struct echo_cursor echo_cursor;

/*
** The test module defined in this file uses four global Tcl variables to
** commicate with test-scripts:
**
**     $::echo_module
**     $::echo_module_sync_fail
**     $::echo_module_begin_fail
**     $::echo_module_cost
**
** The variable ::echo_module is a list. Each time one of the following
** methods is called, one or more elements are appended to the list.
** This is used for automated testing of virtual table modules.
**
** The ::echo_module_sync_fail variable is set by test scripts and read
** by code in this file. If it is set to the name of a real table in the
** the database, then all xSync operations on echo virtual tables that
** use the named table as a backing store will fail.
*/

/* 
** An echo virtual-table object.
**
** echo.vtab.aIndex is an array of booleans. The nth entry is true if 
** the nth column of the real table is the left-most column of an index
** (implicit or otherwise). In other words, if SQLite can optimize
** a query like "SELECT * FROM real_table WHERE col = ?".
**
** Member variable aCol[] contains copies of the column names of the real
** table.
*/
struct echo_vtab {
  sqlite3_vtab base;
  Tcl_Interp *interp;     /* Tcl interpreter containing debug variables */
  sqlite3 *db;            /* Database connection */

  int isPattern;
  char *zThis;            /* Name of the echo table */
  char *zTableName;       /* Name of the real table */
  char *zLogName;         /* Name of the log table */
  int nCol;               /* Number of columns in the real table */
  int *aIndex;            /* Array of size nCol. True if column has an index */
  char **aCol;            /* Array of size nCol. Column names */
};

/* An echo cursor object */
struct echo_cursor {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pStmt;
};

/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
** Examples:
**
**     "abc"   becomes   abc
**     'xyz'   becomes   xyz
**     [pqr]   becomes   pqr
**     `mno`   becomes   mno
*/
static void dequoteString(char *z){
  int quote;
  int i, j;
  if( z==0 ) return;
  quote = z[0];
  switch( quote ){
    case '\'':  break;
    case '"':   break;
    case '`':   break;                /* For MySQL compatibility */
    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
    default:    return;
  }
  for(i=1, j=0; z[i]; i++){
    if( z[i]==quote ){
      if( z[i+1]==quote ){
        z[j++] = quote;
        i++;
      }else{
        z[j++] = 0;
        break;
      }
    }else{
      z[j++] = z[i];
    }
  }
}

/*
** Retrieve the column names for the table named zTab via database
** connection db. SQLITE_OK is returned on success, or an sqlite error
** code otherwise.
**
** If successful, the number of columns is written to *pnCol. *paCol is
** set to point at sqliteMalloc()'d space containing the array of
** nCol column names. The caller is responsible for calling sqliteFree
** on *paCol.
*/
static int getColumnNames(
  sqlite3 *db, 
  const char *zTab,
  char ***paCol, 
  int *pnCol
){
  char **aCol = 0;
  char *zSql;
  sqlite3_stmt *pStmt = 0;
  int rc = SQLITE_OK;
  int nCol = 0;

  /* Prepare the statement "SELECT * FROM <tbl>". The column names
  ** of the result set of the compiled SELECT will be the same as
  ** the column names of table <tbl>.
  */
  zSql = sqlite3MPrintf("SELECT * FROM %Q", zTab);
  if( !zSql ){
    rc = SQLITE_NOMEM;
    goto out;
  }
  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
  sqliteFree(zSql);

  if( rc==SQLITE_OK ){
    int ii;
    int nBytes;
    char *zSpace;
    nCol = sqlite3_column_count(pStmt);

    /* Figure out how much space to allocate for the array of column names 
    ** (including space for the strings themselves). Then allocate it.
    */
    nBytes = sizeof(char *) * nCol;
    for(ii=0; ii<nCol; ii++){
      nBytes += (strlen(sqlite3_column_name(pStmt, ii)) + 1);
    }
    aCol = (char **)sqliteMalloc(nBytes);
    if( !aCol ){
      rc = SQLITE_NOMEM;
      goto out;
    }

    /* Copy the column names into the allocated space and set up the
    ** pointers in the aCol[] array.
    */
    zSpace = (char *)(&aCol[nCol]);
    for(ii=0; ii<nCol; ii++){
      aCol[ii] = zSpace;
      zSpace += sprintf(zSpace, "%s", sqlite3_column_name(pStmt, ii));
      zSpace++;
    }
    assert( (zSpace-nBytes)==(char *)aCol );
  }

  *paCol = aCol;
  *pnCol = nCol;

out:
  sqlite3_finalize(pStmt);
  return rc;
}

/*
** Parameter zTab is the name of a table in database db with nCol 
** columns. This function allocates an array of integers nCol in 
** size and populates it according to any implicit or explicit 
** indices on table zTab.
**
** If successful, SQLITE_OK is returned and *paIndex set to point 
** at the allocated array. Otherwise, an error code is returned.
**
** See comments associated with the member variable aIndex above 
** "struct echo_vtab" for details of the contents of the array.
*/
static int getIndexArray(
  sqlite3 *db,             /* Database connection */
  const char *zTab,        /* Name of table in database db */
  int nCol,
  int **paIndex
){
  sqlite3_stmt *pStmt = 0;
  int *aIndex = 0;
  int rc;
  char *zSql;

  /* Allocate space for the index array */
  aIndex = (int *)sqliteMalloc(sizeof(int) * nCol);
  if( !aIndex ){
    rc = SQLITE_NOMEM;
    goto get_index_array_out;
  }

  /* Compile an sqlite pragma to loop through all indices on table zTab */
  zSql = sqlite3MPrintf("PRAGMA index_list(%s)", zTab);
  if( !zSql ){
    rc = SQLITE_NOMEM;
    goto get_index_array_out;
  }
  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
  sqliteFree(zSql);

  /* For each index, figure out the left-most column and set the 
  ** corresponding entry in aIndex[] to 1.
  */
  while( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
    const char *zIdx = (const char *)sqlite3_column_text(pStmt, 1);
    sqlite3_stmt *pStmt2 = 0;
    zSql = sqlite3MPrintf("PRAGMA index_info(%s)", zIdx);
    if( !zSql ){
      rc = SQLITE_NOMEM;
      goto get_index_array_out;
    }
    rc = sqlite3_prepare(db, zSql, -1, &pStmt2, 0);
    sqliteFree(zSql);
    if( pStmt2 && sqlite3_step(pStmt2)==SQLITE_ROW ){
      int cid = sqlite3_column_int(pStmt2, 1);
      assert( cid>=0 && cid<nCol );
      aIndex[cid] = 1;
    }
    if( pStmt2 ){
      rc = sqlite3_finalize(pStmt2);
    }
    if( rc!=SQLITE_OK ){
      goto get_index_array_out;
    }
  }


get_index_array_out:
  if( pStmt ){
    int rc2 = sqlite3_finalize(pStmt);
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
  }
  if( rc!=SQLITE_OK ){
    sqliteFree(aIndex);
    aIndex = 0;
  }
  *paIndex = aIndex;
  return rc;
}

/*
** Global Tcl variable $echo_module is a list. This routine appends
** the string element zArg to that list in interpreter interp.
*/
static void appendToEchoModule(Tcl_Interp *interp, const char *zArg){
  int flags = (TCL_APPEND_VALUE | TCL_LIST_ELEMENT | TCL_GLOBAL_ONLY);
  Tcl_SetVar(interp, "echo_module", (zArg?zArg:""), flags);
}

/*
** This function is called from within the echo-modules xCreate and
** xConnect methods. The argc and argv arguments are copies of those 
** passed to the calling method. This function is responsible for
** calling sqlite3_declare_vtab() to declare the schema of the virtual
** table being created or connected.
**
** If the constructor was passed just one argument, i.e.:
**
**   CREATE TABLE t1 AS echo(t2);
**
** Then t2 is assumed to be the name of a *real* database table. The
** schema of the virtual table is declared by passing a copy of the 
** CREATE TABLE statement for the real table to sqlite3_declare_vtab().
** Hence, the virtual table should have exactly the same column names and 
** types as the real table.
*/
static int echoDeclareVtab(
  echo_vtab *pVtab, 
  sqlite3 *db 
){
  int rc = SQLITE_OK;

  if( pVtab->zTableName ){
    sqlite3_stmt *pStmt = 0;
    sqlite3_prepare(db, 
        "SELECT sql FROM sqlite_master WHERE type = 'table' AND name = ?",
        -1, &pStmt, 0);
    sqlite3_bind_text(pStmt, 1, pVtab->zTableName, -1, 0);
    if( sqlite3_step(pStmt)==SQLITE_ROW ){
      int rc2;
      const char *zCreateTable = (const char *)sqlite3_column_text(pStmt, 0);
      rc = sqlite3_declare_vtab(db, zCreateTable);
      rc2 = sqlite3_finalize(pStmt);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    } else {
      rc = sqlite3_finalize(pStmt);
      if( rc==SQLITE_OK ){ 
        rc = SQLITE_ERROR;
      }
    }
    if( rc==SQLITE_OK ){
      rc = getColumnNames(db, pVtab->zTableName, &pVtab->aCol, &pVtab->nCol);
    }
    if( rc==SQLITE_OK ){
      rc = getIndexArray(db, pVtab->zTableName, pVtab->nCol, &pVtab->aIndex);
    }
  }

  return rc;
}

/*
** This function frees all runtime structures associated with the virtual
** table pVtab.
*/
static int echoDestructor(sqlite3_vtab *pVtab){
  echo_vtab *p = (echo_vtab*)pVtab;
  sqliteFree(p->aIndex);
  sqliteFree(p->aCol);
  sqliteFree(p->zThis);
  sqliteFree(p->zTableName);
  sqliteFree(p->zLogName);
  sqliteFree(p);
  return 0;
}

/*
** This function is called to do the work of the xConnect() method -
** to allocate the required in-memory structures for a newly connected
** virtual table.
*/
static int echoConstructor(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  int i;
  echo_vtab *pVtab;

  /* Allocate the sqlite3_vtab/echo_vtab structure itself */
  pVtab = sqliteMalloc( sizeof(*pVtab) );
  if( !pVtab ){
    return SQLITE_NOMEM;
  }
  pVtab->interp = (Tcl_Interp *)pAux;
  pVtab->db = db;

  /* Allocate echo_vtab.zThis */
  pVtab->zThis = sqlite3MPrintf("%s", argv[2]);
  if( !pVtab->zThis ){
    echoDestructor((sqlite3_vtab *)pVtab);
    return SQLITE_NOMEM;
  }

  /* Allocate echo_vtab.zTableName */
  if( argc>3 ){
    pVtab->zTableName = sqlite3MPrintf("%s", argv[3]);
    dequoteString(pVtab->zTableName);
    if( pVtab->zTableName && pVtab->zTableName[0]=='*' ){