test7.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 January 09
**
** 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 client/server version of the SQLite library.
** Derived from test4.c.
**
** $Id: test7.c,v 1.4 2006/03/22 22:10:08 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"

/*
** This test only works on UNIX with a THREADSAFE build that includes
** the SQLITE_SERVER option.
*/
#if OS_UNIX && defined(THREADSAFE) && THREADSAFE==1 && \
    defined(SQLITE_SERVER) && !defined(SQLITE_OMIT_SHARED_CACHE)

#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sched.h>
#include <ctype.h>

/*
** Interfaces defined in server.c
*/
int sqlite3_client_open(const char*, sqlite3**);
int sqlite3_client_prepare(sqlite3*,const char*,int,
                           sqlite3_stmt**,const char**);
int sqlite3_client_step(sqlite3_stmt*);
int sqlite3_client_reset(sqlite3_stmt*);
int sqlite3_client_finalize(sqlite3_stmt*);
int sqlite3_client_close(sqlite3*);
int sqlite3_server_start(void);
int sqlite3_server_stop(void);

/*
** Each thread is controlled by an instance of the following
** structure.
*/
typedef struct Thread Thread;
struct Thread {
  /* The first group of fields are writable by the supervisor thread
  ** and read-only to the client threads
  */
  char *zFilename;         /* Name of database file */
  void (*xOp)(Thread*);    /* next operation to do */
  char *zArg;              /* argument usable by xOp */
  volatile int opnum;      /* Operation number */
  volatile int busy;       /* True if this thread is in use */

  /* The next group of fields are writable by the client threads 
  ** but read-only to the superviser thread.
  */
  volatile int completed;  /* Number of operations completed */
  sqlite3 *db;             /* Open database */
  sqlite3_stmt *pStmt;     /* Pending operation */
  char *zErr;              /* operation error */
  char *zStaticErr;        /* Static error message */
  int rc;                  /* operation return code */
  int argc;                /* number of columns in result */
  const char *argv[100];   /* result columns */
  const char *colv[100];   /* result column names */
};

/*
** There can be as many as 26 threads running at once.  Each is named
** by a capital letter: A, B, C, ..., Y, Z.
*/
#define N_THREAD 26
static Thread threadset[N_THREAD];

/*
** The main loop for a thread.  Threads use busy waiting. 
*/
static void *client_main(void *pArg){
  Thread *p = (Thread*)pArg;
  if( p->db ){
    sqlite3_client_close(p->db);
  }
  sqlite3_client_open(p->zFilename, &p->db);
  if( SQLITE_OK!=sqlite3_errcode(p->db) ){
    p->zErr = strdup(sqlite3_errmsg(p->db));
    sqlite3_client_close(p->db);
    p->db = 0;
  }
  p->pStmt = 0;
  p->completed = 1;
  while( p->opnum<=p->completed ) sched_yield();
  while( p->xOp ){
    if( p->zErr && p->zErr!=p->zStaticErr ){
      sqlite3_free(p->zErr);
      p->zErr = 0;
    }
    (*p->xOp)(p);
    p->completed++;
    while( p->opnum<=p->completed ) sched_yield();
  }
  if( p->pStmt ){
    sqlite3_client_finalize(p->pStmt);
    p->pStmt = 0;
  }
  if( p->db ){
    sqlite3_client_close(p->db);
    p->db = 0;
  }
  if( p->zErr && p->zErr!=p->zStaticErr ){
    sqlite3_free(p->zErr);
    p->zErr = 0;
  }
  p->completed++;
  sqlite3_thread_cleanup();
  return 0;
}

/*
** Get a thread ID which is an upper case letter.  Return the index.
** If the argument is not a valid thread ID put an error message in
** the interpreter and return -1.
*/
static int parse_client_id(Tcl_Interp *interp, const char *zArg){
  if( zArg==0 || zArg[0]==0 || zArg[1]!=0 || !isupper((unsigned char)zArg[0]) ){
    Tcl_AppendResult(interp, "thread ID must be an upper case letter", 0);
    return -1;
  }
  return zArg[0] - 'A';
}

/*
** Usage:    client_create NAME  FILENAME
**
** NAME should be an upper case letter.  Start the thread running with
** an open connection to the given database.
*/
static int tcl_client_create(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;
  pthread_t x;
  int rc;

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID FILENAME", 0);
    return TCL_ERROR;
  }
  i = parse_client_id(interp, argv[1]);
  if( i<0 ) return TCL_ERROR;
  if( threadset[i].busy ){
    Tcl_AppendResult(interp, "thread ", argv[1], " is already running", 0);
    return TCL_ERROR;
  }
  threadset[i].busy = 1;
  sqliteFree(threadset[i].zFilename);
  threadset[i].zFilename = sqliteStrDup(argv[2]);
  threadset[i].opnum = 1;
  threadset[i].completed = 0;
  rc = pthread_create(&x, 0, client_main, &threadset[i]);
  if( rc ){
    Tcl_AppendResult(interp, "failed to create the thread", 0);
    sqliteFree(threadset[i].zFilename);
    threadset[i].busy = 0;
    return TCL_ERROR;
  }
  pthread_detach(x);
  sqlite3_server_start();
  return TCL_OK;
}

/*
** Wait for a thread to reach its idle state.
*/
static void client_wait(Thread *p){
  while( p->opnum>p->completed ) sched_yield();
}

/*
** Usage:  client_wait ID
**
** Wait on thread ID to reach its idle state.
*/
static int tcl_client_wait(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID", 0);
    return TCL_ERROR;
  }
  i = parse_client_id(interp, argv[1]);
  if( i<0 ) return TCL_ERROR;
  if( !threadset[i].busy ){
    Tcl_AppendResult(interp, "no such thread", 0);
    return TCL_ERROR;
  }
  client_wait(&threadset[i]);
  return TCL_OK;
}

/*
** Stop a thread.
*/
static void stop_thread(Thread *p){
  client_wait(p);
  p->xOp = 0;
  p->opnum++;
  client_wait(p);
  sqliteFree(p->zArg);
  p->zArg = 0;
  sqliteFree(p->zFilename);
  p->zFilename = 0;
  p->busy = 0;
}

/*
** Usage:  client_halt ID
**
** Cause a client thread to shut itself down.  Wait for the shutdown to be
** completed.  If ID is "*" then stop all client threads.
*/
static int tcl_client_halt(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID", 0);
    return TCL_ERROR;
  }
  if( argv[1][0]=='*' && argv[1][1]==0 ){
    for(i=0; i<N_THREAD; i++){
      if( threadset[i].busy ){
        stop_thread(&threadset[i]);
      }
    }
  }else{
    i = parse_client_id(interp, argv[1]);
    if( i<0 ) return TCL_ERROR;
    if( !threadset[i].busy ){
      Tcl_AppendResult(interp, "no such thread", 0);
      return TCL_ERROR;
    }
    stop_thread(&threadset[i]);
  }

  /* If no client threads are still running, also stop the server */
  for(i=0; i<N_THREAD && threadset[i].busy==0; i++){}
  if( i>=N_THREAD ){
    sqlite3_server_stop();
  }
  return TCL_OK;
}

/*
** Usage: client_argc  ID
**
** Wait on the most recent client_step to complete, then return the
** number of columns in the result set.
*/
static int tcl_client_argc(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;
  char zBuf[100];

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID", 0);
    return TCL_ERROR;
  }
  i = parse_client_id(interp, argv[1]);
  if( i<0 ) return TCL_ERROR;
  if( !threadset[i].busy ){
    Tcl_AppendResult(interp, "no such thread", 0);
    return TCL_ERROR;
  }
  client_wait(&threadset[i]);
  sprintf(zBuf, "%d", threadset[i].argc);
  Tcl_AppendResult(interp, zBuf, 0);
  return TCL_OK;
}

/*
** Usage: client_argv  ID   N
**
** Wait on the most recent client_step to complete, then return the
** value of the N-th columns in the result set.
*/
static int tcl_client_argv(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;
  int n;

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID N", 0);
    return TCL_ERROR;
  }
  i = parse_client_id(interp, argv[1]);
  if( i<0 ) return TCL_ERROR;
  if( !threadset[i].busy ){
    Tcl_AppendResult(interp, "no such thread", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[2], &n) ) return TCL_ERROR;
  client_wait(&threadset[i]);
  if( n<0 || n>=threadset[i].argc ){
    Tcl_AppendResult(interp, "column number out of range", 0);
    return TCL_ERROR;
  }
  Tcl_AppendResult(interp, threadset[i].argv[n], 0);
  return TCL_OK;
}

/*
** Usage: client_colname  ID   N
**
** Wait on the most recent client_step to complete, then return the
** name of the N-th columns in the result set.
*/
static int tcl_client_colname(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  int i;
  int n;

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID N", 0);
    return TCL_ERROR;
  }