/*

** 2002 January 15

**

** 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.

**

*************************************************************************

** This file implements a simple standalone program used to test whether

** or not the SQLite library is threadsafe.

**

** Testing the thread safety of SQLite is difficult because there are very

** few places in the code that are even potentially unsafe, and those

** places execute for very short periods of time.  So even if the library

** is compiled with its mutexes disabled, it is likely to work correctly

** in a multi-threaded program most of the time.  

**

** This file is NOT part of the standard SQLite library.  It is used for

** testing only.

*/

#include "sqlite.h"

#include <pthread.h>

#include <sched.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

/*

** Enable for tracing

*/

static int verbose = 0;

/*

** Come here to die.

*/

static void Exit(int rc){

  exit(rc);

}

extern char *sqlite3_mprintf(const char *zFormat, ...);

extern char *sqlite3_vmprintf(const char *zFormat, va_list);

/*

** When a lock occurs, yield.

*/

static int db_is_locked(void *NotUsed, int iCount){

  /* sched_yield(); */

  if( verbose ) printf("BUSY %s #%d\n", (char*)NotUsed, iCount);

  usleep(100);

  return iCount<25;

}

/*

** Used to accumulate query results by db_query()

*/

struct QueryResult {

  const char *zFile;  /* Filename - used for error reporting */

  int nElem;          /* Number of used entries in azElem[] */

  int nAlloc;         /* Number of slots allocated for azElem[] */

  char **azElem;      /* The result of the query */

};

/*

** The callback function for db_query

*/

static int db_query_callback(

  void *pUser,     /* Pointer to the QueryResult structure */

  int nArg,        /* Number of columns in this result row */

  char **azArg,    /* Text of data in all columns */

  char **NotUsed   /* Names of the columns */

){

  struct QueryResult *pResult = (struct QueryResult*)pUser;

  int i;

  if( pResult->nElem + nArg >= pResult->nAlloc ){

    if( pResult->nAlloc==0 ){

      pResult->nAlloc = nArg+1;

    }else{

      pResult->nAlloc = pResult->nAlloc*2 + nArg + 1;

    }

    pResult->azElem = realloc( pResult->azElem, pResult->nAlloc*sizeof(char*));

    if( pResult->azElem==0 ){

      fprintf(stdout,"%s: malloc failed\n", pResult->zFile);

      return 1;

    }

  }

  if( azArg==0 ) return 0;

  for(i=0; i<nArg; i++){

    pResult->azElem[pResult->nElem++] =

        sqlite3_mprintf("%s",azArg[i] ? azArg[i] : ""); 

  }

  return 0;

}

/*

** Execute a query against the database.  NULL values are returned

** as an empty string.  The list is terminated by a single NULL pointer.

*/

char **db_query(sqlite *db, const char *zFile, const char *zFormat, ...){

  char *zSql;

  int rc;

  char *zErrMsg = 0;

  va_list ap;

  struct QueryResult sResult;

  va_start(ap, zFormat);

  zSql = sqlite3_vmprintf(zFormat, ap);

  va_end(ap);

  memset(&sResult, 0, sizeof(sResult));

  sResult.zFile = zFile;

  if( verbose ) printf("QUERY %s: %s\n", zFile, zSql);

  rc = sqlite3_exec(db, zSql, db_query_callback, &sResult, &zErrMsg);

  if( rc==SQLITE_SCHEMA ){

    if( zErrMsg ) free(zErrMsg);

    rc = sqlite3_exec(db, zSql, db_query_callback, &sResult, &zErrMsg);

  }

  if( verbose ) printf("DONE %s %s\n", zFile, zSql);

  if( zErrMsg ){

    fprintf(stdout,"%s: query failed: %s - %s\n", zFile, zSql, zErrMsg);

    free(zErrMsg);

    free(zSql);

    Exit(1);

  }

  sqlite3_free(zSql);

  if( sResult.azElem==0 ){

    db_query_callback(&sResult, 0, 0, 0);

  }

  sResult.azElem[sResult.nElem] = 0;

  return sResult.azElem;

}

/*

** Execute an SQL statement.

*/

void db_execute(sqlite *db, const char *zFile, const char *zFormat, ...){

  char *zSql;

  int rc;

  char *zErrMsg = 0;

  va_list ap;

  va_start(ap, zFormat);

  zSql = sqlite3_vmprintf(zFormat, ap);

  va_end(ap);

  if( verbose ) printf("EXEC %s: %s\n", zFile, zSql);

  do{

    rc = sqlite3_exec(db, zSql, 0, 0, &zErrMsg);

  }while( rc==SQLITE_BUSY );

  if( verbose ) printf("DONE %s: %s\n", zFile, zSql);

  if( zErrMsg ){

    fprintf(stdout,"%s: command failed: %s - %s\n", zFile, zSql, zErrMsg);

    free(zErrMsg);

    sqlite3_free(zSql);

    Exit(1);

  }

  sqlite3_free(zSql);

}

/*

** Free the results of a db_query() call.

*/

void db_query_free(char **az){

  int i;

  for(i=0; az[i]; i++){

    sqlite3_free(az[i]);

  }

  free(az);

}

/*

** Check results

*/

void db_check(const char *zFile, const char *zMsg, char **az, ...){

  va_list ap;

  int i;

  char *z;

  va_start(ap, az);

  for(i=0; (z = va_arg(ap, char*))!=0; i++){

    if( az[i]==0 || strcmp(az[i],z)!=0 ){

      fprintf(stdout,"%s: %s: bad result in column %d: %s\n",

        zFile, zMsg, i+1, az[i]);

      db_query_free(az);

      Exit(1);

    }

  }

  va_end(ap);

  db_query_free(az);

}

pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

pthread_cond_t sig = PTHREAD_COND_INITIALIZER;

int thread_cnt = 0;

static void *worker_bee(void *pArg){

  const char *zFilename = (char*)pArg;

  char *azErr;

  int i, cnt;

  int t = atoi(zFilename);

  char **az;

  sqlite *db;

  pthread_mutex_lock(&lock);

  thread_cnt++;

  pthread_mutex_unlock(&lock);

  printf("%s: START\n", zFilename);

  fflush(stdout);

  for(cnt=0; cnt<10; cnt++){

    sqlite3_open(&zFilename[2], &db);

    if( db==0 ){

      fprintf(stdout,"%s: can't open\n", zFilename);

      Exit(1);

    }

    sqlite3_busy_handler(db, db_is_locked, zFilename);

    db_execute(db, zFilename, "CREATE TABLE t%d(a,b,c);", t);

    for(i=1; i<=100; i++){

      db_execute(db, zFilename, "INSERT INTO t%d VALUES(%d,%d,%d);",

         t, i, i*2, i*i);

    }

    az = db_query(db, zFilename, "SELECT count(*) FROM t%d", t);

    db_check(zFilename, "tX size", az, "100", 0);  

    az = db_query(db, zFilename, "SELECT avg(b) FROM t%d", t);

    db_check(zFilename, "tX avg", az, "101", 0);  

    db_execute(db, zFilename, "DELETE FROM t%d WHERE a>50", t);

    az = db_query(db, zFilename, "SELECT avg(b) FROM t%d", t);

    db_check(zFilename, "tX avg2", az, "51", 0);

    for(i=1; i<=50; i++){

      char z1[30], z2[30];

      az = db_query(db, zFilename, "SELECT b, c FROM t%d WHERE a=%d", t, i);

      sprintf(z1, "%d", i*2);

      sprintf(z2, "%d", i*i);

      db_check(zFilename, "readback", az, z1, z2, 0);

    }

    db_execute(db, zFilename, "DROP TABLE t%d;", t);

    sqlite3_close(db);

  }

  printf("%s: END\n", zFilename);

  /* unlink(zFilename); */

  fflush(stdout);

  pthread_mutex_lock(&lock);

  thread_cnt--;

  if( thread_cnt<=0 ){

    pthread_cond_signal(&sig);

  }

  pthread_mutex_unlock(&lock);

  return 0;

}

int main(int argc, char **argv){

  char *zFile;

  int i, n;

  pthread_t id;

  if( argc>2 && strcmp(argv[1], "-v")==0 ){

    verbose = 1;

    argc--;

    argv++;

  }

  if( argc<2 || (n=atoi(argv[1]))<1 ) n = 10;

  for(i=0; i<n; i++){

    char zBuf[200];

    sprintf(zBuf, "testdb-%d", (i+1)/2);

    unlink(zBuf);

  }

  for(i=0; i<n; i++){

    zFile = sqlite3_mprintf("%d.testdb-%d", i%2+1, (i+2)/2);

    if( (i%2)==0 ){

      /* Remove both the database file and any old journal for the file

      ** being used by this thread and the next one. */

      char *zDb = &zFile[2];

      char *zJournal = sqlite3_mprintf("%s-journal", zDb);

      unlink(zDb);

      unlink(zJournal);

      free(zJournal);

    }

    pthread_create(&id, 0, worker_bee, (void*)zFile);

    pthread_detach(id);

  }

  pthread_mutex_lock(&lock);

  while( thread_cnt>0 ){

    pthread_cond_wait(&sig, &lock);

  }

  pthread_mutex_unlock(&lock);

  for(i=0; i<n; i++){

    char zBuf[200];

    sprintf(zBuf, "testdb-%d", (i+1)/2);

    unlink(zBuf);

  }

  return 0;

}