webkitgtk-2.10.2webkitgtk-2.10.2

1 files changed, 139 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/JSStringJoiner.h b/Source/JavaScriptCore/runtime/JSStringJoiner.h
new file mode 100644
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+++ b/Source/JavaScriptCore/runtime/JSStringJoiner.h
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2012-2015 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.
+ */
+
+#ifndef JSStringJoiner_h
+#define JSStringJoiner_h
+
+#include "ExceptionHelpers.h"
+#include "JSCJSValue.h"
+
+namespace JSC {
+
+class JSStringJoiner {
+public:
+    JSStringJoiner(ExecState&, LChar separator, unsigned stringCount);
+    JSStringJoiner(ExecState&, StringView separator, unsigned stringCount);
+
+    void append(ExecState&, JSValue);
+    void appendEmptyString();
+
+    JSValue join(ExecState&);
+
+private:
+    void append(StringViewWithUnderlyingString&&);
+    void append8Bit(const String&);
+    void appendLiteral(const Identifier&);
+    unsigned joinedLength(ExecState&) const;
+
+    LChar m_singleCharacterSeparator;
+    StringView m_separator;
+    Vector<StringViewWithUnderlyingString> m_strings;
+    Checked<unsigned, RecordOverflow> m_accumulatedStringsLength;
+    bool m_isAll8Bit { true };
+};
+
+inline JSStringJoiner::JSStringJoiner(ExecState& state, StringView separator, unsigned stringCount)
+    : m_separator(separator)
+    , m_isAll8Bit(m_separator.is8Bit())
+{
+    if (!m_strings.tryReserveCapacity(stringCount))
+        throwOutOfMemoryError(&state);
+}
+
+inline JSStringJoiner::JSStringJoiner(ExecState& state, LChar separator, unsigned stringCount)
+    : m_singleCharacterSeparator(separator)
+    , m_separator { &m_singleCharacterSeparator, 1 }
+{
+    if (!m_strings.tryReserveCapacity(stringCount))
+        throwOutOfMemoryError(&state);
+}
+
+ALWAYS_INLINE void JSStringJoiner::append(StringViewWithUnderlyingString&& string)
+{
+    m_accumulatedStringsLength += string.view.length();
+    m_isAll8Bit = m_isAll8Bit && string.view.is8Bit();
+    m_strings.uncheckedAppend(WTF::move(string));
+}
+
+ALWAYS_INLINE void JSStringJoiner::append8Bit(const String& string)
+{
+    ASSERT(string.is8Bit());
+    m_accumulatedStringsLength += string.length();
+    m_strings.uncheckedAppend({ string, string });
+}
+
+ALWAYS_INLINE void JSStringJoiner::appendLiteral(const Identifier& literal)
+{
+    m_accumulatedStringsLength += literal.length();
+    ASSERT(literal.string().is8Bit());
+    m_strings.uncheckedAppend({ literal.string(), { } });
+}
+
+ALWAYS_INLINE void JSStringJoiner::appendEmptyString()
+{
+    m_strings.uncheckedAppend({ { }, { } });
+}
+
+ALWAYS_INLINE void JSStringJoiner::append(ExecState& state, JSValue value)
+{
+    // The following code differs from using the result of JSValue::toString in the following ways:
+    // 1) It's inlined more than JSValue::toString is.
+    // 2) It includes conversion to WTF::String in a way that avoids allocating copies of substrings.
+    // 3) It doesn't create a JSString for numbers, true, or false.
+    // 4) It turns undefined and null into the empty string instead of "undefined" and "null".
+    // 5) It uses optimized code paths for all the cases known to be 8-bit and for the empty string.
+
+    if (value.isCell()) {
+        if (value.asCell()->isString()) {
+            append(asString(value)->viewWithUnderlyingString(state));
+            return;
+        }
+        append(value.toString(&state)->viewWithUnderlyingString(state));
+        return;
+    }
+
+    if (value.isInt32()) {
+        append8Bit(state.vm().numericStrings.add(value.asInt32()));
+        return;
+    }
+    if (value.isDouble()) {
+        append8Bit(state.vm().numericStrings.add(value.asDouble()));
+        return;
+    }
+    if (value.isTrue()) {
+        append8Bit(state.vm().propertyNames->trueKeyword.string());
+        return;
+    }
+    if (value.isFalse()) {
+        append8Bit(state.vm().propertyNames->falseKeyword.string());
+        return;
+    }
+    ASSERT(value.isUndefinedOrNull());
+    appendEmptyString();
+}
+
+}
+
+#endif