Imported QtWebKit TP3 (git b57bc6801f1876c3220d5a4bfea33d620d477443)

Change-Id: I3b1d8a2808782c9f34d50240000e20cb38d3680f Reviewed-by: Konstantin Tokarev <annulen@yandex.ru>
author: Konstantin Tokarev <annulen@yandex.ru> 2016-08-25 19:20:41 +0300
committer: Konstantin Tokarev <annulen@yandex.ru> 2017-02-02 12:30:55 +0000
commit: 6882a04fb36642862b11efe514251d32070c3d65 (patch)
tree: b7959826000b061fd5ccc7512035c7478742f7b0 /Source/WTF/wtf/ParallelHelperPool.cpp
parent: ab6df191029eeeb0b0f16f127d553265659f739e (diff)
1 files changed, 241 insertions, 0 deletions
diff --git a/Source/WTF/wtf/ParallelHelperPool.cpp b/Source/WTF/wtf/ParallelHelperPool.cpp
new file mode 100644
index 000000000..cd15f7d0c
--- /dev/null
+++ b/Source/WTF/wtf/ParallelHelperPool.cpp
@@ -0,0 +1,241 @@
+/*
+ * Copyright (C) 2015 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "ParallelHelperPool.h"
+
+#include "DataLog.h"
+#include "StringPrintStream.h"
+
+namespace WTF {
+
+ParallelHelperClient::ParallelHelperClient(RefPtr<ParallelHelperPool> pool)
+    : m_pool(pool)
+{
+    LockHolder locker(m_pool->m_lock);
+    RELEASE_ASSERT(!m_pool->m_isDying);
+    m_pool->m_clients.append(this);
+}
+
+ParallelHelperClient::~ParallelHelperClient()
+{
+    LockHolder locker(m_pool->m_lock);
+    finish(locker);
+
+    for (size_t i = 0; i < m_pool->m_clients.size(); ++i) {
+        if (m_pool->m_clients[i] == this) {
+            m_pool->m_clients[i] = m_pool->m_clients.last();
+            m_pool->m_clients.removeLast();
+            break;
+        }
+    }
+}
+
+void ParallelHelperClient::setTask(RefPtr<SharedTask<void ()>> task)
+{
+    LockHolder locker(m_pool->m_lock);
+    RELEASE_ASSERT(!m_task);
+    m_task = task;
+    m_pool->didMakeWorkAvailable(locker);
+}
+
+void ParallelHelperClient::finish()
+{
+    LockHolder locker(m_pool->m_lock);
+    finish(locker);
+}
+
+void ParallelHelperClient::doSomeHelping()
+{
+    RefPtr<SharedTask<void ()>> task;
+    {
+        LockHolder locker(m_pool->m_lock);
+        task = claimTask(locker);
+        if (!task)
+            return;
+    }
+
+    runTask(task);
+}
+
+void ParallelHelperClient::runTaskInParallel(RefPtr<SharedTask<void ()>> task)
+{
+    setTask(task);
+    doSomeHelping();
+    finish();
+}
+
+void ParallelHelperClient::finish(const LockHolder&)
+{
+    m_task = nullptr;
+    while (m_numActive)
+        m_pool->m_workCompleteCondition.wait(m_pool->m_lock);
+}
+
+RefPtr<SharedTask<void ()>> ParallelHelperClient::claimTask(const LockHolder&)
+{
+    if (!m_task)
+        return nullptr;
+    
+    m_numActive++;
+    return m_task;
+}
+
+void ParallelHelperClient::runTask(RefPtr<SharedTask<void ()>> task)
+{
+    RELEASE_ASSERT(m_numActive);
+    RELEASE_ASSERT(task);
+
+    task->run();
+
+    {
+        LockHolder locker(m_pool->m_lock);
+        RELEASE_ASSERT(m_numActive);
+        // No new task could have been installed, since we were still active.
+        RELEASE_ASSERT(!m_task || m_task == task);
+        m_task = nullptr;
+        m_numActive--;
+        if (!m_numActive)
+            m_pool->m_workCompleteCondition.notifyAll();
+    }
+}
+
+ParallelHelperPool::ParallelHelperPool()
+{
+}
+
+ParallelHelperPool::~ParallelHelperPool()
+{
+    RELEASE_ASSERT(m_clients.isEmpty());
+    
+    {
+        LockHolder locker(m_lock);
+        m_isDying = true;
+        m_workAvailableCondition.notifyAll();
+    }
+
+    for (ThreadIdentifier threadIdentifier : m_threads)
+        waitForThreadCompletion(threadIdentifier);
+}
+
+void ParallelHelperPool::ensureThreads(unsigned numThreads)
+{
+    LockHolder locker(m_lock);
+    if (numThreads < m_numThreads)
+        return;
+    m_numThreads = numThreads;
+    if (getClientWithTask(locker))
+        didMakeWorkAvailable(locker);
+}
+
+void ParallelHelperPool::doSomeHelping()
+{
+    ParallelHelperClient* client;
+    RefPtr<SharedTask<void ()>> task;
+    {
+        LockHolder locker(m_lock);
+        client = getClientWithTask(locker);
+        if (!client)
+            return;
+        task = client->claimTask(locker);
+    }
+
+    client->runTask(task);
+}
+
+void ParallelHelperPool::didMakeWorkAvailable(const LockHolder&)
+{
+    while (m_numThreads > m_threads.size()) {
+        ThreadIdentifier threadIdentifier = createThread(
+            "WTF Parallel Helper Thread",
+            [this] () {
+                helperThreadBody();
+            });
+        m_threads.append(threadIdentifier);
+    }
+    m_workAvailableCondition.notifyAll();
+}
+
+void ParallelHelperPool::helperThreadBody()
+{
+    for (;;) {
+        ParallelHelperClient* client;
+        RefPtr<SharedTask<void ()>> task;
+
+        {
+            LockHolder locker(m_lock);
+            client = waitForClientWithTask(locker);
+            if (!client) {
+                RELEASE_ASSERT(m_isDying);
+                return;
+            }
+
+            task = client->claimTask(locker);
+        }
+
+        client->runTask(task);
+    }
+}
+
+bool ParallelHelperPool::hasClientWithTask(const LockHolder& locker)
+{
+    return !!getClientWithTask(locker);
+}
+
+ParallelHelperClient* ParallelHelperPool::getClientWithTask(const LockHolder&)
+{
+    // We load-balance by being random.
+    unsigned startIndex = m_random.getUint32(m_clients.size());
+    for (unsigned index = startIndex; index < m_clients.size(); ++index) {
+        ParallelHelperClient* client = m_clients[index];
+        if (client->m_task)
+            return client;
+    }
+    for (unsigned index = 0; index < startIndex; ++index) {
+        ParallelHelperClient* client = m_clients[index];
+        if (client->m_task)
+            return client;
+    }
+
+    return nullptr;
+}
+
+ParallelHelperClient* ParallelHelperPool::waitForClientWithTask(const LockHolder& locker)
+{
+    for (;;) {
+        // It might be quittin' time.
+        if (m_isDying)
+            return nullptr;
+
+        if (ParallelHelperClient* result = getClientWithTask(locker))
+            return result;
+
+        // Wait until work becomes available.
+        m_workAvailableCondition.wait(m_lock);
+    }
+}
+
+} // namespace WTF
+
author	Konstantin Tokarev <annulen@yandex.ru>	2016-08-25 19:20:41 +0300
committer	Konstantin Tokarev <annulen@yandex.ru>	2017-02-02 12:30:55 +0000
commit	6882a04fb36642862b11efe514251d32070c3d65 (patch)
tree	b7959826000b061fd5ccc7512035c7478742f7b0 /Source/WTF/wtf/ParallelHelperPool.cpp
parent	ab6df191029eeeb0b0f16f127d553265659f739e (diff)