WIP: Introduce CompressibleString

third_party/WebKit/Source/platform/text/CompressableString.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "platform/text/CompressableString.h"
+
+// TODO: This seems illegal: Fix checkdeps?

[haraken, 2015/11/24 11:15:42]

We should add a public API to talk with component/compression.

+#include "components/compression/compression_utils.h"
+#include "wtf/Assertions.h"
+#include "wtf/Partitions.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+void CompressableStringImpl::purgeMemory()

[haraken, 2015/11/24 11:15:42]

What are you intending to do with the purgeMemory()?

+{
+}
+
+CompressableStringImpl::CompressableStringImpl(PassRefPtr<StringImpl> impl)
+    : m_impl(impl)
+    , m_compressedData(nullptr)
+    , m_originalLength(m_impl->length())
+    , m_is8Bit(m_impl->is8Bit())
+{
+}
+
+unsigned CompressableStringImpl::sizeInBytes() const
+{
+    if (is8Bit())
+        return m_originalLength * 2;
+    return m_originalLength;
+}
+
+String CompressableStringImpl::toString()
+{
+    if (UNLIKELY(isCompressed()))
+        uncompress();
+    return m_impl.get();
+}
+
+const LChar* CompressableStringImpl::characters8()
+{
+    return toString().characters8();
+}
+
+const UChar* CompressableStringImpl::characters16()
+{
+    return toString().characters16();
+}
+
+void CompressableStringImpl::compress()
+{
+    ASSERT(m_impl);
+    ASSERT(!isCompressed());
+
+    // TODO(hajimehoshi): Now components offers funcitons accepting only
+    // std::strings. This is not efficient. We should offer char* version.
+    std::string in, out;
+    if (m_is8Bit)
+        in = std::string(reinterpret_cast<const char*>(m_impl->characters8()), m_impl->sizeInBytes());
+    else
+        in = std::string(reinterpret_cast<const char*>(m_impl->characters16()), m_impl->sizeInBytes());
+    compression::GzipCompress(in, &out);
+
+    m_impl = nullptr;
+    m_compressedData = SharedBuffer::create(out.c_str(), out.size());
+}
+
+void CompressableStringImpl::uncompress()
+{
+    ASSERT(m_compressedData);
+    ASSERT(!m_impl);
+
+    std::string in(m_compressedData->data(), m_compressedData->size());
+    std::string out;
+    compression::GzipUncompress(in, &out);
+
+    if (m_is8Bit) {
+        LChar* data = nullptr;
+        m_impl = StringImpl::createUninitialized(out.size() / sizeof(LChar), data);
+        memcpy(data, out.c_str(), out.size());
+    } else {
+        UChar* data = nullptr;
+        m_impl = StringImpl::createUninitialized(out.size() / sizeof(UChar), data);
+        memcpy(data, out.c_str(), out.size());
+    }
+
+    m_compressedData = nullptr;
+    ASSERT(m_originalLength == m_impl->length());
+}
+
+CompressableString::CompressableString()
+    : m_impl(nullptr)
+{
+}
+
+CompressableString::CompressableString(const CompressableString& rhs)
+    : m_impl(rhs.m_impl)
+{
+}
+
+CompressableString::CompressableString(PassRefPtr<StringImpl> impl)
+    : m_impl(impl ? adoptRef(new CompressableStringImpl(impl)) : nullptr)
+{
+}
+
+void CompressableString::compress() const
+{
+    m_impl->compress();
+}
+
+void CompressableString::uncompress() const
+{
+    m_impl->uncompress();
+}
+
+} // namespace blink