Move bundled copy of sqlite one level deeper to better separate it...

third_party/sqlite/src/test_server.c

Index: third_party/sqlite/src/test_server.c
===================================================================
--- third_party/sqlite/src/test_server.c	(revision 56608)
+++ third_party/sqlite/src/test_server.c	(working copy)
@@ -1,493 +0,0 @@
-/*
-** 2006 January 07
-**
-** 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.
-**
-******************************************************************************
-**
-** $Id: test_server.c,v 1.8 2008/06/26 10:41:19 danielk1977 Exp $
-**
-** This file contains demonstration code.  Nothing in this file gets compiled
-** or linked into the SQLite library unless you use a non-standard option:
-**
-**      -DSQLITE_SERVER=1
-**
-** The configure script will never generate a Makefile with the option
-** above.  You will need to manually modify the Makefile if you want to
-** include any of the code from this file in your project.  Or, at your
-** option, you may copy and paste the code from this file and
-** thereby avoiding a recompile of SQLite.
-**
-**
-** This source file demonstrates how to use SQLite to create an SQL database 
-** server thread in a multiple-threaded program.  One or more client threads
-** send messages to the server thread and the server thread processes those
-** messages in the order received and returns the results to the client.
-**
-** One might ask:  "Why bother?  Why not just let each thread connect
-** to the database directly?"  There are a several of reasons to
-** prefer the client/server approach.
-**
-**    (1)  Some systems (ex: Redhat9) have broken threading implementations
-**         that prevent SQLite database connections from being used in
-**         a thread different from the one where they were created.  With
-**         the client/server approach, all database connections are created
-**         and used within the server thread.  Client calls to the database
-**         can be made from multiple threads (though not at the same time!)
-**
-**    (2)  Beginning with SQLite version 3.3.0, when two or more 
-**         connections to the same database occur within the same thread,
-**         they can optionally share their database cache.  This reduces
-**         I/O and memory requirements.  Cache shared is controlled using
-**         the sqlite3_enable_shared_cache() API.
-**
-**    (3)  Database connections on a shared cache use table-level locking
-**         instead of file-level locking for improved concurrency.
-**
-**    (4)  Database connections on a shared cache can by optionally
-**         set to READ UNCOMMITTED isolation.  (The default isolation for
-**         SQLite is SERIALIZABLE.)  When this occurs, readers will
-**         never be blocked by a writer and writers will not be
-**         blocked by readers.  There can still only be a single writer
-**         at a time, but multiple readers can simultaneously exist with
-**         that writer.  This is a huge increase in concurrency.
-**
-** To summarize the rational for using a client/server approach: prior
-** to SQLite version 3.3.0 it probably was not worth the trouble.  But
-** with SQLite version 3.3.0 and beyond you can get significant performance
-** and concurrency improvements and memory usage reductions by going
-** client/server.
-**
-** Note:  The extra features of version 3.3.0 described by points (2)
-** through (4) above are only available if you compile without the
-** option -DSQLITE_OMIT_SHARED_CACHE. 
-**
-** Here is how the client/server approach works:  The database server
-** thread is started on this procedure:
-**
-**       void *sqlite3_server(void *NotUsed);
-**
-** The sqlite_server procedure runs as long as the g.serverHalt variable
-** is false.  A mutex is used to make sure no more than one server runs
-** at a time.  The server waits for messages to arrive on a message
-** queue and processes the messages in order.
-**
-** Two convenience routines are provided for starting and stopping the
-** server thread:
-**
-**       void sqlite3_server_start(void);
-**       void sqlite3_server_stop(void);
-**
-** Both of the convenience routines return immediately.  Neither will
-** ever give an error.  If a server is already started or already halted,
-** then the routines are effectively no-ops.
-**
-** Clients use the following interfaces:
-**
-**       sqlite3_client_open
-**       sqlite3_client_prepare
-**       sqlite3_client_step
-**       sqlite3_client_reset
-**       sqlite3_client_finalize
-**       sqlite3_client_close
-**
-** These interfaces work exactly like the standard core SQLite interfaces
-** having the same names without the "_client_" infix.  Many other SQLite
-** interfaces can be used directly without having to send messages to the
-** server as long as SQLITE_ENABLE_MEMORY_MANAGEMENT is not defined.
-** The following interfaces fall into this second category:
-**
-**       sqlite3_bind_*
-**       sqlite3_changes
-**       sqlite3_clear_bindings
-**       sqlite3_column_*
-**       sqlite3_complete
-**       sqlite3_create_collation
-**       sqlite3_create_function
-**       sqlite3_data_count
-**       sqlite3_db_handle
-**       sqlite3_errcode
-**       sqlite3_errmsg
-**       sqlite3_last_insert_rowid
-**       sqlite3_total_changes
-**       sqlite3_transfer_bindings
-**
-** A single SQLite connection (an sqlite3* object) or an SQLite statement
-** (an sqlite3_stmt* object) should only be passed to a single interface
-** function at a time.  The connections and statements can be passed from
-** any thread to any of the functions listed in the second group above as
-** long as the same connection is not in use by two threads at once and
-** as long as SQLITE_ENABLE_MEMORY_MANAGEMENT is not defined.  Additional
-** information about the SQLITE_ENABLE_MEMORY_MANAGEMENT constraint is
-** below.
-**
-** The busy handler for all database connections should remain turned
-** off.  That means that any lock contention will cause the associated
-** sqlite3_client_step() call to return immediately with an SQLITE_BUSY
-** error code.  If a busy handler is enabled and lock contention occurs,
-** then the entire server thread will block.  This will cause not only
-** the requesting client to block but every other database client as
-** well.  It is possible to enhance the code below so that lock
-** contention will cause the message to be placed back on the top of
-** the queue to be tried again later.  But such enhanced processing is
-** not included here, in order to keep the example simple.
-**
-** This example code assumes the use of pthreads.  Pthreads
-** implementations are available for windows.  (See, for example
-** http://sourceware.org/pthreads-win32/announcement.html.)  Or, you
-** can translate the locking and thread synchronization code to use
-** windows primitives easily enough.  The details are left as an
-** exercise to the reader.
-**
-**** Restrictions Associated With SQLITE_ENABLE_MEMORY_MANAGEMENT ****
-**
-** If you compile with SQLITE_ENABLE_MEMORY_MANAGEMENT defined, then
-** SQLite includes code that tracks how much memory is being used by
-** each thread.  These memory counts can become confused if memory
-** is allocated by one thread and then freed by another.  For that
-** reason, when SQLITE_ENABLE_MEMORY_MANAGEMENT is used, all operations
-** that might allocate or free memory should be performanced in the same
-** thread that originally created the database connection.  In that case,
-** many of the operations that are listed above as safe to be performed
-** in separate threads would need to be sent over to the server to be
-** done there.  If SQLITE_ENABLE_MEMORY_MANAGEMENT is defined, then
-** the following functions can be used safely from different threads
-** without messing up the allocation counts:
-**
-**       sqlite3_bind_parameter_name
-**       sqlite3_bind_parameter_index
-**       sqlite3_changes
-**       sqlite3_column_blob
-**       sqlite3_column_count
-**       sqlite3_complete
-**       sqlite3_data_count
-**       sqlite3_db_handle
-**       sqlite3_errcode
-**       sqlite3_errmsg
-**       sqlite3_last_insert_rowid
-**       sqlite3_total_changes
-**
-** The remaining functions are not thread-safe when memory management
-** is enabled.  So one would have to define some new interface routines
-** along the following lines:
-**
-**       sqlite3_client_bind_*
-**       sqlite3_client_clear_bindings
-**       sqlite3_client_column_*
-**       sqlite3_client_create_collation
-**       sqlite3_client_create_function
-**       sqlite3_client_transfer_bindings
-**
-** The example code in this file is intended for use with memory
-** management turned off.  So the implementation of these additional
-** client interfaces is left as an exercise to the reader.
-**
-** It may seem surprising to the reader that the list of safe functions
-** above does not include things like sqlite3_bind_int() or
-** sqlite3_column_int().  But those routines might, in fact, allocate
-** or deallocate memory.  In the case of sqlite3_bind_int(), if the
-** parameter was previously bound to a string that string might need
-** to be deallocated before the new integer value is inserted.  In
-** the case of sqlite3_column_int(), the value of the column might be
-** a UTF-16 string which will need to be converted to UTF-8 then into
-** an integer.
-*/
-
-/* Include this to get the definition of SQLITE_THREADSAFE, in the
-** case that default values are used.
-*/
-#include "sqliteInt.h"
-
-/*
-** Only compile the code in this file on UNIX with a SQLITE_THREADSAFE build
-** and only if the SQLITE_SERVER macro is defined.
-*/
-#if defined(SQLITE_SERVER) && !defined(SQLITE_OMIT_SHARED_CACHE)
-#if defined(SQLITE_OS_UNIX) && OS_UNIX && SQLITE_THREADSAFE
-
-/*
-** We require only pthreads and the public interface of SQLite.
-*/
-#include <pthread.h>
-#include "sqlite3.h"
-
-/*
-** Messages are passed from client to server and back again as 
-** instances of the following structure.
-*/
-typedef struct SqlMessage SqlMessage;
-struct SqlMessage {
-  int op;                      /* Opcode for the message */
-  sqlite3 *pDb;                /* The SQLite connection */
-  sqlite3_stmt *pStmt;         /* A specific statement */
-  int errCode;                 /* Error code returned */
-  const char *zIn;             /* Input filename or SQL statement */
-  int nByte;                   /* Size of the zIn parameter for prepare() */
-  const char *zOut;            /* Tail of the SQL statement */
-  SqlMessage *pNext;           /* Next message in the queue */
-  SqlMessage *pPrev;           /* Previous message in the queue */
-  pthread_mutex_t clientMutex; /* Hold this mutex to access the message */
-  pthread_cond_t clientWakeup; /* Signal to wake up the client */
-};
-
-/*
-** Legal values for SqlMessage.op
-*/
-#define MSG_Open       1  /* sqlite3_open(zIn, &pDb) */
-#define MSG_Prepare    2  /* sqlite3_prepare(pDb, zIn, nByte, &pStmt, &zOut) */
-#define MSG_Step       3  /* sqlite3_step(pStmt) */
-#define MSG_Reset      4  /* sqlite3_reset(pStmt) */
-#define MSG_Finalize   5  /* sqlite3_finalize(pStmt) */
-#define MSG_Close      6  /* sqlite3_close(pDb) */
-#define MSG_Done       7  /* Server has finished with this message */
-
-
-/*
-** State information about the server is stored in a static variable
-** named "g" as follows:
-*/
-static struct ServerState {
-  pthread_mutex_t queueMutex;   /* Hold this mutex to access the msg queue */
-  pthread_mutex_t serverMutex;  /* Held by the server while it is running */
-  pthread_cond_t serverWakeup;  /* Signal this condvar to wake up the server */
-  volatile int serverHalt;      /* Server halts itself when true */
-  SqlMessage *pQueueHead;       /* Head of the message queue */
-  SqlMessage *pQueueTail;       /* Tail of the message queue */
-} g = {
-  PTHREAD_MUTEX_INITIALIZER,
-  PTHREAD_MUTEX_INITIALIZER,
-  PTHREAD_COND_INITIALIZER,
-};
-
-/*
-** Send a message to the server.  Block until we get a reply.
-**
-** The mutex and condition variable in the message are uninitialized
-** when this routine is called.  This routine takes care of 
-** initializing them and destroying them when it has finished.
-*/
-static void sendToServer(SqlMessage *pMsg){
-  /* Initialize the mutex and condition variable on the message
-  */
-  pthread_mutex_init(&pMsg->clientMutex, 0);
-  pthread_cond_init(&pMsg->clientWakeup, 0);
-
-  /* Add the message to the head of the server's message queue.
-  */
-  pthread_mutex_lock(&g.queueMutex);
-  pMsg->pNext = g.pQueueHead;
-  if( g.pQueueHead==0 ){
-    g.pQueueTail = pMsg;
-  }else{
-    g.pQueueHead->pPrev = pMsg;
-  }
-  pMsg->pPrev = 0;
-  g.pQueueHead = pMsg;
-  pthread_mutex_unlock(&g.queueMutex);
-
-  /* Signal the server that the new message has be queued, then
-  ** block waiting for the server to process the message.
-  */
-  pthread_mutex_lock(&pMsg->clientMutex);
-  pthread_cond_signal(&g.serverWakeup);
-  while( pMsg->op!=MSG_Done ){
-    pthread_cond_wait(&pMsg->clientWakeup, &pMsg->clientMutex);
-  }
-  pthread_mutex_unlock(&pMsg->clientMutex);
-
-  /* Destroy the mutex and condition variable of the message.
-  */
-  pthread_mutex_destroy(&pMsg->clientMutex);
-  pthread_cond_destroy(&pMsg->clientWakeup);
-}
-
-/*
-** The following 6 routines are client-side implementations of the
-** core SQLite interfaces:
-**
-**        sqlite3_open
-**        sqlite3_prepare
-**        sqlite3_step
-**        sqlite3_reset
-**        sqlite3_finalize
-**        sqlite3_close
-**
-** Clients should use the following client-side routines instead of 
-** the core routines above.
-**
-**        sqlite3_client_open
-**        sqlite3_client_prepare
-**        sqlite3_client_step
-**        sqlite3_client_reset
-**        sqlite3_client_finalize
-**        sqlite3_client_close
-**
-** Each of these routines creates a message for the desired operation,
-** sends that message to the server, waits for the server to process
-** then message and return a response.
-*/
-int sqlite3_client_open(const char *zDatabaseName, sqlite3 **ppDb){
-  SqlMessage msg;
-  msg.op = MSG_Open;
-  msg.zIn = zDatabaseName;
-  sendToServer(&msg);
-  *ppDb = msg.pDb;
-  return msg.errCode;
-}
-int sqlite3_client_prepare(
-  sqlite3 *pDb,
-  const char *zSql,
-  int nByte,
-  sqlite3_stmt **ppStmt,
-  const char **pzTail
-){
-  SqlMessage msg;
-  msg.op = MSG_Prepare;
-  msg.pDb = pDb;
-  msg.zIn = zSql;
-  msg.nByte = nByte;
-  sendToServer(&msg);
-  *ppStmt = msg.pStmt;
-  if( pzTail ) *pzTail = msg.zOut;
-  return msg.errCode;
-}
-int sqlite3_client_step(sqlite3_stmt *pStmt){
-  SqlMessage msg;
-  msg.op = MSG_Step;
-  msg.pStmt = pStmt;
-  sendToServer(&msg);
-  return msg.errCode;
-}
-int sqlite3_client_reset(sqlite3_stmt *pStmt){
-  SqlMessage msg;
-  msg.op = MSG_Reset;
-  msg.pStmt = pStmt;
-  sendToServer(&msg);
-  return msg.errCode;
-}
-int sqlite3_client_finalize(sqlite3_stmt *pStmt){
-  SqlMessage msg;
-  msg.op = MSG_Finalize;
-  msg.pStmt = pStmt;
-  sendToServer(&msg);
-  return msg.errCode;
-}
-int sqlite3_client_close(sqlite3 *pDb){
-  SqlMessage msg;
-  msg.op = MSG_Close;
-  msg.pDb = pDb;
-  sendToServer(&msg);
-  return msg.errCode;
-}
-
-/*
-** This routine implements the server.  To start the server, first
-** make sure g.serverHalt is false, then create a new detached thread
-** on this procedure.  See the sqlite3_server_start() routine below
-** for an example.  This procedure loops until g.serverHalt becomes
-** true.
-*/
-void *sqlite3_server(void *NotUsed){
-  if( pthread_mutex_trylock(&g.serverMutex) ){
-    return 0;  /* Another server is already running */
-  }
-  sqlite3_enable_shared_cache(1);
-  while( !g.serverHalt ){
-    SqlMessage *pMsg;
-
-    /* Remove the last message from the message queue.
-    */
-    pthread_mutex_lock(&g.queueMutex);
-    while( g.pQueueTail==0 && g.serverHalt==0 ){
-      pthread_cond_wait(&g.serverWakeup, &g.queueMutex);
-    }
-    pMsg = g.pQueueTail;
-    if( pMsg ){
-      if( pMsg->pPrev ){
-        pMsg->pPrev->pNext = 0;
-      }else{
-        g.pQueueHead = 0;
-      }
-      g.pQueueTail = pMsg->pPrev;
-    }
-    pthread_mutex_unlock(&g.queueMutex);
-    if( pMsg==0 ) break;
-
-    /* Process the message just removed
-    */
-    pthread_mutex_lock(&pMsg->clientMutex);
-    switch( pMsg->op ){
-      case MSG_Open: {
-        pMsg->errCode = sqlite3_open(pMsg->zIn, &pMsg->pDb);
-        break;
-      }
-      case MSG_Prepare: {
-        pMsg->errCode = sqlite3_prepare(pMsg->pDb, pMsg->zIn, pMsg->nByte,
-                                        &pMsg->pStmt, &pMsg->zOut);
-        break;
-      }
-      case MSG_Step: {
-        pMsg->errCode = sqlite3_step(pMsg->pStmt);
-        break;
-      }
-      case MSG_Reset: {
-        pMsg->errCode = sqlite3_reset(pMsg->pStmt);
-        break;
-      }
-      case MSG_Finalize: {
-        pMsg->errCode = sqlite3_finalize(pMsg->pStmt);
-        break;
-      }
-      case MSG_Close: {
-        pMsg->errCode = sqlite3_close(pMsg->pDb);
-        break;
-      }
-    }
-
-    /* Signal the client that the message has been processed.
-    */
-    pMsg->op = MSG_Done;
-    pthread_mutex_unlock(&pMsg->clientMutex);
-    pthread_cond_signal(&pMsg->clientWakeup);
-  }
-  sqlite3_thread_cleanup();
-  pthread_mutex_unlock(&g.serverMutex);
-  return 0;
-}
-
-/*
-** Start a server thread if one is not already running.  If there
-** is aleady a server thread running, the new thread will quickly
-** die and this routine is effectively a no-op.
-*/
-void sqlite3_server_start(void){
-  pthread_t x;
-  int rc;
-  g.serverHalt = 0;
-  rc = pthread_create(&x, 0, sqlite3_server, 0);
-  if( rc==0 ){
-    pthread_detach(x);
-  }
-}
-
-/*
-** If a server thread is running, then stop it.  If no server is
-** running, this routine is effectively a no-op.
-**
-** This routine waits until the server has actually stopped before
-** returning.
-*/
-void sqlite3_server_stop(void){
-  g.serverHalt = 1;
-  pthread_cond_broadcast(&g.serverWakeup);
-  pthread_mutex_lock(&g.serverMutex);
-  pthread_mutex_unlock(&g.serverMutex);
-}
-
-#endif /* defined(SQLITE_OS_UNIX) && OS_UNIX && SQLITE_THREADSAFE */
-#endif /* defined(SQLITE_SERVER) */