webkitgtk-2.10.2webkitgtk-2.10.2

1 files changed, 137 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/SmallStrings.cpp b/Source/JavaScriptCore/runtime/SmallStrings.cpp
new file mode 100644
index 000000000..9c6a43ae2
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+++ b/Source/JavaScriptCore/runtime/SmallStrings.cpp
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2008, 2010 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 "SmallStrings.h"
+
+#include "HeapRootVisitor.h"
+#include "JSGlobalObject.h"
+#include "JSString.h"
+#include "JSCInlines.h"
+#include <wtf/Noncopyable.h>
+#include <wtf/text/StringImpl.h>
+
+namespace JSC {
+
+class SmallStringsStorage {
+    WTF_MAKE_NONCOPYABLE(SmallStringsStorage); WTF_MAKE_FAST_ALLOCATED;
+public:
+    SmallStringsStorage();
+
+    StringImpl* rep(unsigned char character)
+    {
+        return m_reps[character].get();
+    }
+
+private:
+    static const unsigned singleCharacterStringCount = maxSingleCharacterString + 1;
+
+    RefPtr<StringImpl> m_reps[singleCharacterStringCount];
+};
+
+SmallStringsStorage::SmallStringsStorage()
+{
+    LChar* characterBuffer = 0;
+    RefPtr<StringImpl> baseString = StringImpl::createUninitialized(singleCharacterStringCount, characterBuffer);
+    for (unsigned i = 0; i < singleCharacterStringCount; ++i) {
+        characterBuffer[i] = i;
+        m_reps[i] = AtomicStringImpl::add(PassRefPtr<StringImpl>(StringImpl::createSubstringSharingImpl(baseString, i, 1)).get());
+    }
+}
+
+SmallStrings::SmallStrings()
+    : m_emptyString(0)
+#define JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE(name) , m_##name(0)
+    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE)
+#undef JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE
+    , m_nullObjectString(nullptr)
+    , m_undefinedObjectString(nullptr)
+    , m_needsToBeVisited(true)
+{
+    COMPILE_ASSERT(singleCharacterStringCount == sizeof(m_singleCharacterStrings) / sizeof(m_singleCharacterStrings[0]), IsNumCharactersConstInSyncWithClassUsage);
+
+    for (unsigned i = 0; i < singleCharacterStringCount; ++i)
+        m_singleCharacterStrings[i] = 0;
+}
+
+void SmallStrings::initializeCommonStrings(VM& vm)
+{
+    createEmptyString(&vm);
+    for (unsigned i = 0; i <= maxSingleCharacterString; ++i)
+        createSingleCharacterString(&vm, i);
+#define JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE(name) initialize(&vm, m_##name, #name);
+    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE)
+#undef JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE
+    initialize(&vm, m_nullObjectString, "[object Null]");
+    initialize(&vm, m_undefinedObjectString, "[object Undefined]");
+}
+
+void SmallStrings::visitStrongReferences(SlotVisitor& visitor)
+{
+    m_needsToBeVisited = false;
+    visitor.appendUnbarrieredPointer(&m_emptyString);
+    for (unsigned i = 0; i <= maxSingleCharacterString; ++i)
+        visitor.appendUnbarrieredPointer(m_singleCharacterStrings + i);
+#define JSC_COMMON_STRINGS_ATTRIBUTE_VISIT(name) visitor.appendUnbarrieredPointer(&m_##name);
+    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_VISIT)
+#undef JSC_COMMON_STRINGS_ATTRIBUTE_VISIT
+    visitor.appendUnbarrieredPointer(&m_nullObjectString);
+    visitor.appendUnbarrieredPointer(&m_undefinedObjectString);
+}
+
+SmallStrings::~SmallStrings()
+{
+}
+
+void SmallStrings::createEmptyString(VM* vm)
+{
+    ASSERT(!m_emptyString);
+    m_emptyString = JSString::createHasOtherOwner(*vm, StringImpl::empty());
+    m_needsToBeVisited = true;
+}
+
+void SmallStrings::createSingleCharacterString(VM* vm, unsigned char character)
+{
+    if (!m_storage)
+        m_storage = std::make_unique<SmallStringsStorage>();
+    ASSERT(!m_singleCharacterStrings[character]);
+    m_singleCharacterStrings[character] = JSString::createHasOtherOwner(*vm, PassRefPtr<StringImpl>(m_storage->rep(character)));
+    m_needsToBeVisited = true;
+}
+
+StringImpl* SmallStrings::singleCharacterStringRep(unsigned char character)
+{
+    if (!m_storage)
+        m_storage = std::make_unique<SmallStringsStorage>();
+    return m_storage->rep(character);
+}
+
+void SmallStrings::initialize(VM* vm, JSString*& string, const char* value)
+{
+    string = JSString::create(*vm, Identifier::fromString(vm, value).impl());
+    m_needsToBeVisited = true;
+}
+
+} // namespace JSC