From 63847496f14c813a5d80efd5b7de0f1294ffe1e3 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 13 Apr 2024 16:07:11 +0200 Subject: Adding upstream version 3.45.1. Signed-off-by: Daniel Baumann --- src/threads.c | 274 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 274 insertions(+) create mode 100644 src/threads.c (limited to 'src/threads.c') diff --git a/src/threads.c b/src/threads.c new file mode 100644 index 0000000..f128d69 --- /dev/null +++ b/src/threads.c @@ -0,0 +1,274 @@ +/* +** 2012 July 21 +** +** 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 presents a simple cross-platform threading interface for +** use internally by SQLite. +** +** A "thread" can be created using sqlite3ThreadCreate(). This thread +** runs independently of its creator until it is joined using +** sqlite3ThreadJoin(), at which point it terminates. +** +** Threads do not have to be real. It could be that the work of the +** "thread" is done by the main thread at either the sqlite3ThreadCreate() +** or sqlite3ThreadJoin() call. This is, in fact, what happens in +** single threaded systems. Nothing in SQLite requires multiple threads. +** This interface exists so that applications that want to take advantage +** of multiple cores can do so, while also allowing applications to stay +** single-threaded if desired. +*/ +#include "sqliteInt.h" +#if SQLITE_OS_WIN +# include "os_win.h" +#endif + +#if SQLITE_MAX_WORKER_THREADS>0 + +/********************************* Unix Pthreads ****************************/ +#if SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) && SQLITE_THREADSAFE>0 + +#define SQLITE_THREADS_IMPLEMENTED 1 /* Prevent the single-thread code below */ +#include + +/* A running thread */ +struct SQLiteThread { + pthread_t tid; /* Thread ID */ + int done; /* Set to true when thread finishes */ + void *pOut; /* Result returned by the thread */ + void *(*xTask)(void*); /* The thread routine */ + void *pIn; /* Argument to the thread */ +}; + +/* Create a new thread */ +int sqlite3ThreadCreate( + SQLiteThread **ppThread, /* OUT: Write the thread object here */ + void *(*xTask)(void*), /* Routine to run in a separate thread */ + void *pIn /* Argument passed into xTask() */ +){ + SQLiteThread *p; + int rc; + + assert( ppThread!=0 ); + assert( xTask!=0 ); + /* This routine is never used in single-threaded mode */ + assert( sqlite3GlobalConfig.bCoreMutex!=0 ); + + *ppThread = 0; + p = sqlite3Malloc(sizeof(*p)); + if( p==0 ) return SQLITE_NOMEM_BKPT; + memset(p, 0, sizeof(*p)); + p->xTask = xTask; + p->pIn = pIn; + /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a + ** function that returns SQLITE_ERROR when passed the argument 200, that + ** forces worker threads to run sequentially and deterministically + ** for testing purposes. */ + if( sqlite3FaultSim(200) ){ + rc = 1; + }else{ + rc = pthread_create(&p->tid, 0, xTask, pIn); + } + if( rc ){ + p->done = 1; + p->pOut = xTask(pIn); + } + *ppThread = p; + return SQLITE_OK; +} + +/* Get the results of the thread */ +int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ + int rc; + + assert( ppOut!=0 ); + if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT; + if( p->done ){ + *ppOut = p->pOut; + rc = SQLITE_OK; + }else{ + rc = pthread_join(p->tid, ppOut) ? SQLITE_ERROR : SQLITE_OK; + } + sqlite3_free(p); + return rc; +} + +#endif /* SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) */ +/******************************** End Unix Pthreads *************************/ + + +/********************************* Win32 Threads ****************************/ +#if SQLITE_OS_WIN_THREADS + +#define SQLITE_THREADS_IMPLEMENTED 1 /* Prevent the single-thread code below */ +#include + +/* A running thread */ +struct SQLiteThread { + void *tid; /* The thread handle */ + unsigned id; /* The thread identifier */ + void *(*xTask)(void*); /* The routine to run as a thread */ + void *pIn; /* Argument to xTask */ + void *pResult; /* Result of xTask */ +}; + +/* Thread procedure Win32 compatibility shim */ +static unsigned __stdcall sqlite3ThreadProc( + void *pArg /* IN: Pointer to the SQLiteThread structure */ +){ + SQLiteThread *p = (SQLiteThread *)pArg; + + assert( p!=0 ); +#if 0 + /* + ** This assert appears to trigger spuriously on certain + ** versions of Windows, possibly due to _beginthreadex() + ** and/or CreateThread() not fully setting their thread + ** ID parameter before starting the thread. + */ + assert( p->id==GetCurrentThreadId() ); +#endif + assert( p->xTask!=0 ); + p->pResult = p->xTask(p->pIn); + + _endthreadex(0); + return 0; /* NOT REACHED */ +} + +/* Create a new thread */ +int sqlite3ThreadCreate( + SQLiteThread **ppThread, /* OUT: Write the thread object here */ + void *(*xTask)(void*), /* Routine to run in a separate thread */ + void *pIn /* Argument passed into xTask() */ +){ + SQLiteThread *p; + + assert( ppThread!=0 ); + assert( xTask!=0 ); + *ppThread = 0; + p = sqlite3Malloc(sizeof(*p)); + if( p==0 ) return SQLITE_NOMEM_BKPT; + /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a + ** function that returns SQLITE_ERROR when passed the argument 200, that + ** forces worker threads to run sequentially and deterministically + ** (via the sqlite3FaultSim() term of the conditional) for testing + ** purposes. */ + if( sqlite3GlobalConfig.bCoreMutex==0 || sqlite3FaultSim(200) ){ + memset(p, 0, sizeof(*p)); + }else{ + p->xTask = xTask; + p->pIn = pIn; + p->tid = (void*)_beginthreadex(0, 0, sqlite3ThreadProc, p, 0, &p->id); + if( p->tid==0 ){ + memset(p, 0, sizeof(*p)); + } + } + if( p->xTask==0 ){ + p->id = GetCurrentThreadId(); + p->pResult = xTask(pIn); + } + *ppThread = p; + return SQLITE_OK; +} + +DWORD sqlite3Win32Wait(HANDLE hObject); /* os_win.c */ + +/* Get the results of the thread */ +int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ + DWORD rc; + BOOL bRc; + + assert( ppOut!=0 ); + if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT; + if( p->xTask==0 ){ + /* assert( p->id==GetCurrentThreadId() ); */ + rc = WAIT_OBJECT_0; + assert( p->tid==0 ); + }else{ + assert( p->id!=0 && p->id!=GetCurrentThreadId() ); + rc = sqlite3Win32Wait((HANDLE)p->tid); + assert( rc!=WAIT_IO_COMPLETION ); + bRc = CloseHandle((HANDLE)p->tid); + assert( bRc ); + } + if( rc==WAIT_OBJECT_0 ) *ppOut = p->pResult; + sqlite3_free(p); + return (rc==WAIT_OBJECT_0) ? SQLITE_OK : SQLITE_ERROR; +} + +#endif /* SQLITE_OS_WIN_THREADS */ +/******************************** End Win32 Threads *************************/ + + +/********************************* Single-Threaded **************************/ +#ifndef SQLITE_THREADS_IMPLEMENTED +/* +** This implementation does not actually create a new thread. It does the +** work of the thread in the main thread, when either the thread is created +** or when it is joined +*/ + +/* A running thread */ +struct SQLiteThread { + void *(*xTask)(void*); /* The routine to run as a thread */ + void *pIn; /* Argument to xTask */ + void *pResult; /* Result of xTask */ +}; + +/* Create a new thread */ +int sqlite3ThreadCreate( + SQLiteThread **ppThread, /* OUT: Write the thread object here */ + void *(*xTask)(void*), /* Routine to run in a separate thread */ + void *pIn /* Argument passed into xTask() */ +){ + SQLiteThread *p; + + assert( ppThread!=0 ); + assert( xTask!=0 ); + *ppThread = 0; + p = sqlite3Malloc(sizeof(*p)); + if( p==0 ) return SQLITE_NOMEM_BKPT; + if( (SQLITE_PTR_TO_INT(p)/17)&1 ){ + p->xTask = xTask; + p->pIn = pIn; + }else{ + p->xTask = 0; + p->pResult = xTask(pIn); + } + *ppThread = p; + return SQLITE_OK; +} + +/* Get the results of the thread */ +int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){ + + assert( ppOut!=0 ); + if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT; + if( p->xTask ){ + *ppOut = p->xTask(p->pIn); + }else{ + *ppOut = p->pResult; + } + sqlite3_free(p); + +#if defined(SQLITE_TEST) + { + void *pTstAlloc = sqlite3Malloc(10); + if (!pTstAlloc) return SQLITE_NOMEM_BKPT; + sqlite3_free(pTstAlloc); + } +#endif + + return SQLITE_OK; +} + +#endif /* !defined(SQLITE_THREADS_IMPLEMENTED) */ +/****************************** End Single-Threaded *************************/ +#endif /* SQLITE_MAX_WORKER_THREADS>0 */ -- cgit v1.2.3