Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 498 insertions, 0 deletions

diff --git a/nsprpub/pr/src/threads/prrwlock.c b/nsprpub/pr/src/threads/prrwlock.c
new file mode 100644
index 0000000000..0cb51e5bdf
--- /dev/null
+++ b/nsprpub/pr/src/threads/prrwlock.c
@@ -0,0 +1,498 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "primpl.h"
+
+#include <string.h>
+
+#if defined(HPUX) && defined(_PR_PTHREADS)
+
+#include <pthread.h>
+#define HAVE_UNIX98_RWLOCK
+#define RWLOCK_T pthread_rwlock_t
+#define RWLOCK_INIT(lock) pthread_rwlock_init(lock, NULL)
+#define RWLOCK_DESTROY(lock) pthread_rwlock_destroy(lock)
+#define RWLOCK_RDLOCK(lock) pthread_rwlock_rdlock(lock)
+#define RWLOCK_WRLOCK(lock) pthread_rwlock_wrlock(lock)
+#define RWLOCK_UNLOCK(lock) pthread_rwlock_unlock(lock)
+
+#elif defined(SOLARIS) && (defined(_PR_PTHREADS) \
+        || defined(_PR_GLOBAL_THREADS_ONLY))
+
+#include <synch.h>
+#define HAVE_UI_RWLOCK
+#define RWLOCK_T rwlock_t
+#define RWLOCK_INIT(lock) rwlock_init(lock, USYNC_THREAD, NULL)
+#define RWLOCK_DESTROY(lock) rwlock_destroy(lock)
+#define RWLOCK_RDLOCK(lock) rw_rdlock(lock)
+#define RWLOCK_WRLOCK(lock) rw_wrlock(lock)
+#define RWLOCK_UNLOCK(lock) rw_unlock(lock)
+
+#endif
+
+/*
+ * Reader-writer lock
+ */
+struct PRRWLock {
+    char            *rw_name;           /* lock name                    */
+    PRUint32        rw_rank;            /* rank of the lock             */
+
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    RWLOCK_T        rw_lock;
+#else
+    PRLock          *rw_lock;
+    PRInt32         rw_lock_cnt;        /* ==  0, if unlocked           */
+    /* == -1, if write-locked       */
+    /* > 0  , # of read locks       */
+    PRUint32        rw_reader_cnt;      /* number of waiting readers    */
+    PRUint32        rw_writer_cnt;      /* number of waiting writers    */
+    PRCondVar       *rw_reader_waitq;   /* cvar for readers             */
+    PRCondVar       *rw_writer_waitq;   /* cvar for writers             */
+#ifdef DEBUG
+    PRThread        *rw_owner;          /* lock owner for write-lock    */
+#endif
+#endif
+};
+
+#ifdef DEBUG
+#define _PR_RWLOCK_RANK_ORDER_DEBUG /* enable deadlock detection using
+                                       rank-order for locks
+                                    */
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+
+static PRUintn  pr_thread_rwlock_key;           /* TPD key for lock stack */
+static PRUintn  pr_thread_rwlock_alloc_failed;
+
+#define _PR_RWLOCK_RANK_ORDER_LIMIT 10
+
+typedef struct thread_rwlock_stack {
+    PRInt32     trs_index;                                  /* top of stack */
+    PRRWLock    *trs_stack[_PR_RWLOCK_RANK_ORDER_LIMIT];    /* stack of lock
+                                                               pointers */
+
+} thread_rwlock_stack;
+
+static void _PR_SET_THREAD_RWLOCK_RANK(PRRWLock *rwlock);
+static PRUint32 _PR_GET_THREAD_RWLOCK_RANK(void);
+static void _PR_UNSET_THREAD_RWLOCK_RANK(PRRWLock *rwlock);
+static void _PR_RELEASE_LOCK_STACK(void *lock_stack);
+
+#endif
+
+/*
+ * Reader/Writer Locks
+ */
+
+/*
+ * PR_NewRWLock
+ *      Create a reader-writer lock, with the given lock rank and lock name
+ *
+ */
+
+PR_IMPLEMENT(PRRWLock *)
+PR_NewRWLock(PRUint32 lock_rank, const char *lock_name)
+{
+    PRRWLock *rwlock;
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    int err;
+#endif
+
+    if (!_pr_initialized) {
+        _PR_ImplicitInitialization();
+    }
+
+    rwlock = PR_NEWZAP(PRRWLock);
+    if (rwlock == NULL) {
+        return NULL;
+    }
+
+    rwlock->rw_rank = lock_rank;
+    if (lock_name != NULL) {
+        rwlock->rw_name = (char*) PR_Malloc(strlen(lock_name) + 1);
+        if (rwlock->rw_name == NULL) {
+            PR_DELETE(rwlock);
+            return(NULL);
+        }
+        strcpy(rwlock->rw_name, lock_name);
+    } else {
+        rwlock->rw_name = NULL;
+    }
+
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    err = RWLOCK_INIT(&rwlock->rw_lock);
+    if (err != 0) {
+        PR_SetError(PR_UNKNOWN_ERROR, err);
+        PR_Free(rwlock->rw_name);
+        PR_DELETE(rwlock);
+        return NULL;
+    }
+    return rwlock;
+#else
+    rwlock->rw_lock = PR_NewLock();
+    if (rwlock->rw_lock == NULL) {
+        goto failed;
+    }
+    rwlock->rw_reader_waitq = PR_NewCondVar(rwlock->rw_lock);
+    if (rwlock->rw_reader_waitq == NULL) {
+        goto failed;
+    }
+    rwlock->rw_writer_waitq = PR_NewCondVar(rwlock->rw_lock);
+    if (rwlock->rw_writer_waitq == NULL) {
+        goto failed;
+    }
+    rwlock->rw_reader_cnt = 0;
+    rwlock->rw_writer_cnt = 0;
+    rwlock->rw_lock_cnt = 0;
+    return rwlock;
+
+failed:
+    if (rwlock->rw_reader_waitq != NULL) {
+        PR_DestroyCondVar(rwlock->rw_reader_waitq);
+    }
+    if (rwlock->rw_lock != NULL) {
+        PR_DestroyLock(rwlock->rw_lock);
+    }
+    PR_Free(rwlock->rw_name);
+    PR_DELETE(rwlock);
+    return NULL;
+#endif
+}
+
+/*
+** Destroy the given RWLock "lock".
+*/
+PR_IMPLEMENT(void)
+PR_DestroyRWLock(PRRWLock *rwlock)
+{
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    int err;
+    err = RWLOCK_DESTROY(&rwlock->rw_lock);
+    PR_ASSERT(err == 0);
+#else
+    PR_ASSERT(rwlock->rw_reader_cnt == 0);
+    PR_DestroyCondVar(rwlock->rw_reader_waitq);
+    PR_DestroyCondVar(rwlock->rw_writer_waitq);
+    PR_DestroyLock(rwlock->rw_lock);
+#endif
+    if (rwlock->rw_name != NULL) {
+        PR_Free(rwlock->rw_name);
+    }
+    PR_DELETE(rwlock);
+}
+
+/*
+** Read-lock the RWLock.
+*/
+PR_IMPLEMENT(void)
+PR_RWLock_Rlock(PRRWLock *rwlock)
+{
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    int err;
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+    /*
+     * assert that rank ordering is not violated; the rank of 'rwlock' should
+     * be equal to or greater than the highest rank of all the locks held by
+     * the thread.
+     */
+    PR_ASSERT((rwlock->rw_rank == PR_RWLOCK_RANK_NONE) ||
+              (rwlock->rw_rank >= _PR_GET_THREAD_RWLOCK_RANK()));
+#endif
+
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    err = RWLOCK_RDLOCK(&rwlock->rw_lock);
+    PR_ASSERT(err == 0);
+#else
+    PR_Lock(rwlock->rw_lock);
+    /*
+     * wait if write-locked or if a writer is waiting; preference for writers
+     */
+    while ((rwlock->rw_lock_cnt < 0) ||
+           (rwlock->rw_writer_cnt > 0)) {
+        rwlock->rw_reader_cnt++;
+        PR_WaitCondVar(rwlock->rw_reader_waitq, PR_INTERVAL_NO_TIMEOUT);
+        rwlock->rw_reader_cnt--;
+    }
+    /*
+     * Increment read-lock count
+     */
+    rwlock->rw_lock_cnt++;
+
+    PR_Unlock(rwlock->rw_lock);
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+    /*
+     * update thread's lock rank
+     */
+    if (rwlock->rw_rank != PR_RWLOCK_RANK_NONE) {
+        _PR_SET_THREAD_RWLOCK_RANK(rwlock);
+    }
+#endif
+}
+
+/*
+** Write-lock the RWLock.
+*/
+PR_IMPLEMENT(void)
+PR_RWLock_Wlock(PRRWLock *rwlock)
+{
+#if defined(DEBUG)
+    PRThread *me = PR_GetCurrentThread();
+#endif
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    int err;
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+    /*
+     * assert that rank ordering is not violated; the rank of 'rwlock' should
+     * be equal to or greater than the highest rank of all the locks held by
+     * the thread.
+     */
+    PR_ASSERT((rwlock->rw_rank == PR_RWLOCK_RANK_NONE) ||
+              (rwlock->rw_rank >= _PR_GET_THREAD_RWLOCK_RANK()));
+#endif
+
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    err = RWLOCK_WRLOCK(&rwlock->rw_lock);
+    PR_ASSERT(err == 0);
+#else
+    PR_Lock(rwlock->rw_lock);
+    /*
+     * wait if read locked
+     */
+    while (rwlock->rw_lock_cnt != 0) {
+        rwlock->rw_writer_cnt++;
+        PR_WaitCondVar(rwlock->rw_writer_waitq, PR_INTERVAL_NO_TIMEOUT);
+        rwlock->rw_writer_cnt--;
+    }
+    /*
+     * apply write lock
+     */
+    rwlock->rw_lock_cnt--;
+    PR_ASSERT(rwlock->rw_lock_cnt == -1);
+#ifdef DEBUG
+    PR_ASSERT(me != NULL);
+    rwlock->rw_owner = me;
+#endif
+    PR_Unlock(rwlock->rw_lock);
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+    /*
+     * update thread's lock rank
+     */
+    if (rwlock->rw_rank != PR_RWLOCK_RANK_NONE) {
+        _PR_SET_THREAD_RWLOCK_RANK(rwlock);
+    }
+#endif
+}
+
+/*
+** Unlock the RW lock.
+*/
+PR_IMPLEMENT(void)
+PR_RWLock_Unlock(PRRWLock *rwlock)
+{
+#if defined(DEBUG)
+    PRThread *me = PR_GetCurrentThread();
+#endif
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    int err;
+#endif
+
+#if defined(HAVE_UNIX98_RWLOCK) || defined(HAVE_UI_RWLOCK)
+    err = RWLOCK_UNLOCK(&rwlock->rw_lock);
+    PR_ASSERT(err == 0);
+#else
+    PR_Lock(rwlock->rw_lock);
+    /*
+     * lock must be read or write-locked
+     */
+    PR_ASSERT(rwlock->rw_lock_cnt != 0);
+    if (rwlock->rw_lock_cnt > 0) {
+
+        /*
+         * decrement read-lock count
+         */
+        rwlock->rw_lock_cnt--;
+        if (rwlock->rw_lock_cnt == 0) {
+            /*
+             * lock is not read-locked anymore; wakeup a waiting writer
+             */
+            if (rwlock->rw_writer_cnt > 0) {
+                PR_NotifyCondVar(rwlock->rw_writer_waitq);
+            }
+        }
+    } else {
+        PR_ASSERT(rwlock->rw_lock_cnt == -1);
+
+        rwlock->rw_lock_cnt = 0;
+#ifdef DEBUG
+        PR_ASSERT(rwlock->rw_owner == me);
+        rwlock->rw_owner = NULL;
+#endif
+        /*
+         * wakeup a writer, if present; preference for writers
+         */
+        if (rwlock->rw_writer_cnt > 0) {
+            PR_NotifyCondVar(rwlock->rw_writer_waitq);
+        }
+        /*
+         * else, wakeup all readers, if any
+         */
+        else if (rwlock->rw_reader_cnt > 0) {
+            PR_NotifyAllCondVar(rwlock->rw_reader_waitq);
+        }
+    }
+    PR_Unlock(rwlock->rw_lock);
+#endif
+
+#ifdef _PR_RWLOCK_RANK_ORDER_DEBUG
+    /*
+     * update thread's lock rank
+     */
+    if (rwlock->rw_rank != PR_RWLOCK_RANK_NONE) {
+        _PR_UNSET_THREAD_RWLOCK_RANK(rwlock);
+    }
+#endif
+    return;
+}
+
+#ifndef _PR_RWLOCK_RANK_ORDER_DEBUG
+
+void _PR_InitRWLocks(void) { }
+
+#else
+
+void _PR_InitRWLocks(void)
+{
+    /*
+     * allocated thread-private-data index for rwlock list
+     */
+    if (PR_NewThreadPrivateIndex(&pr_thread_rwlock_key,
+                                 _PR_RELEASE_LOCK_STACK) == PR_FAILURE) {
+        pr_thread_rwlock_alloc_failed = 1;
+        return;
+    }
+}
+
+/*
+ * _PR_SET_THREAD_RWLOCK_RANK
+ *      Set a thread's lock rank, which is the highest of the ranks of all
+ *      the locks held by the thread. Pointers to the locks are added to a
+ *      per-thread list, which is anchored off a thread-private data key.
+ */
+
+static void
+_PR_SET_THREAD_RWLOCK_RANK(PRRWLock *rwlock)
+{
+    thread_rwlock_stack *lock_stack;
+    PRStatus rv;
+
+    /*
+     * allocate a lock stack
+     */
+    if ((lock_stack = PR_GetThreadPrivate(pr_thread_rwlock_key)) == NULL) {
+        lock_stack = (thread_rwlock_stack *)
+                     PR_CALLOC(1 * sizeof(thread_rwlock_stack));
+        if (lock_stack) {
+            rv = PR_SetThreadPrivate(pr_thread_rwlock_key, lock_stack);
+            if (rv == PR_FAILURE) {
+                PR_DELETE(lock_stack);
+                pr_thread_rwlock_alloc_failed = 1;
+                return;
+            }
+        } else {
+            pr_thread_rwlock_alloc_failed = 1;
+            return;
+        }
+    }
+    /*
+     * add rwlock to lock stack, if limit is not exceeded
+     */
+    if (lock_stack) {
+        if (lock_stack->trs_index < _PR_RWLOCK_RANK_ORDER_LIMIT) {
+            lock_stack->trs_stack[lock_stack->trs_index++] = rwlock;
+        }
+    }
+}
+
+static void
+_PR_RELEASE_LOCK_STACK(void *lock_stack)
+{
+    PR_ASSERT(lock_stack);
+    PR_DELETE(lock_stack);
+}
+
+/*
+ * _PR_GET_THREAD_RWLOCK_RANK
+ *
+ *      return thread's lock rank. If thread-private-data for the lock
+ *      stack is not allocated, return PR_RWLOCK_RANK_NONE.
+ */
+
+static PRUint32
+_PR_GET_THREAD_RWLOCK_RANK(void)
+{
+    thread_rwlock_stack *lock_stack;
+
+    lock_stack = PR_GetThreadPrivate(pr_thread_rwlock_key);
+    if (lock_stack == NULL || lock_stack->trs_index == 0) {
+        return (PR_RWLOCK_RANK_NONE);
+    }
+    else {
+        return(lock_stack->trs_stack[lock_stack->trs_index - 1]->rw_rank);
+    }
+}
+
+/*
+ * _PR_UNSET_THREAD_RWLOCK_RANK
+ *
+ *      remove the rwlock from the lock stack. Since locks may not be
+ *      unlocked in a FIFO order, the entire lock stack is searched.
+ */
+
+static void
+_PR_UNSET_THREAD_RWLOCK_RANK(PRRWLock *rwlock)
+{
+    thread_rwlock_stack *lock_stack;
+    int new_index = 0, index, done = 0;
+
+    lock_stack = PR_GetThreadPrivate(pr_thread_rwlock_key);
+
+    PR_ASSERT(lock_stack != NULL);
+
+    for (index = lock_stack->trs_index - 1; index >= 0; index--) {
+        if (!done && (lock_stack->trs_stack[index] == rwlock))  {
+            /*
+             * reset the slot for rwlock
+             */
+            lock_stack->trs_stack[index] = NULL;
+            done = 1;
+        }
+        /*
+         * search for the lowest-numbered empty slot, above which there are
+         * no non-empty slots
+         */
+        if (!new_index && (lock_stack->trs_stack[index] != NULL)) {
+            new_index = index + 1;
+        }
+        if (done && new_index) {
+            break;
+        }
+    }
+    /*
+     * set top of stack to highest numbered empty slot
+     */
+    lock_stack->trs_index = new_index;
+
+}
+
+#endif  /* _PR_RWLOCK_RANK_ORDER_DEBUG */