1 /*
2 * Copyright (C) 2009 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "config.h"
27 #include "bindings/v8/V8StringResource.h"
28
29 #include "bindings/v8/V8Binding.h"
30 #include "core/inspector/BindingVisitors.h"
31 #include "wtf/MainThread.h"
32
33 namespace WebCore {
34
35 template<class StringClass> struct StringTraits {
36 static const StringClass& fromStringResource(WebCoreStringResourceBase*);
37 template <typename V8StringTrait>
38 static StringClass fromV8String(v8::Handle<v8::String>, int);
39 };
40
41 template<>
42 struct StringTraits<String> {
fromStringResourceWebCore::StringTraits43 static const String& fromStringResource(WebCoreStringResourceBase* resource)
44 {
45 return resource->webcoreString();
46 }
47 template <typename V8StringTrait>
48 static String fromV8String(v8::Handle<v8::String>, int);
49 };
50
51 template<>
52 struct StringTraits<AtomicString> {
fromStringResourceWebCore::StringTraits53 static const AtomicString& fromStringResource(WebCoreStringResourceBase* resource)
54 {
55 return resource->atomicString();
56 }
57 template <typename V8StringTrait>
58 static AtomicString fromV8String(v8::Handle<v8::String>, int);
59 };
60
61 struct V8StringTwoBytesTrait {
62 typedef UChar CharType;
writeWebCore::V8StringTwoBytesTrait63 ALWAYS_INLINE static void write(v8::Handle<v8::String> v8String, CharType* buffer, int length)
64 {
65 v8String->Write(reinterpret_cast<uint16_t*>(buffer), 0, length);
66 }
67 };
68
69 struct V8StringOneByteTrait {
70 typedef LChar CharType;
writeWebCore::V8StringOneByteTrait71 ALWAYS_INLINE static void write(v8::Handle<v8::String> v8String, CharType* buffer, int length)
72 {
73 v8String->WriteOneByte(buffer, 0, length);
74 }
75 };
76
77 template <typename V8StringTrait>
fromV8String(v8::Handle<v8::String> v8String,int length)78 String StringTraits<String>::fromV8String(v8::Handle<v8::String> v8String, int length)
79 {
80 ASSERT(v8String->Length() == length);
81 typename V8StringTrait::CharType* buffer;
82 String result = String::createUninitialized(length, buffer);
83 V8StringTrait::write(v8String, buffer, length);
84 return result;
85 }
86
87 template <typename V8StringTrait>
fromV8String(v8::Handle<v8::String> v8String,int length)88 AtomicString StringTraits<AtomicString>::fromV8String(v8::Handle<v8::String> v8String, int length)
89 {
90 ASSERT(v8String->Length() == length);
91 static const int inlineBufferSize = 32 / sizeof(typename V8StringTrait::CharType);
92 if (length <= inlineBufferSize) {
93 typename V8StringTrait::CharType inlineBuffer[inlineBufferSize];
94 V8StringTrait::write(v8String, inlineBuffer, length);
95 return AtomicString(inlineBuffer, length);
96 }
97 typename V8StringTrait::CharType* buffer;
98 String string = String::createUninitialized(length, buffer);
99 V8StringTrait::write(v8String, buffer, length);
100 return AtomicString(string);
101 }
102
103 template<typename StringType>
v8StringToWebCoreString(v8::Handle<v8::String> v8String,ExternalMode external)104 StringType v8StringToWebCoreString(v8::Handle<v8::String> v8String, ExternalMode external)
105 {
106 {
107 // This portion of this function is very hot in certain Dromeao benchmarks.
108 v8::String::Encoding encoding;
109 v8::String::ExternalStringResourceBase* resource = v8String->GetExternalStringResourceBase(&encoding);
110 if (LIKELY(!!resource)) {
111 WebCoreStringResourceBase* base;
112 if (encoding == v8::String::ONE_BYTE_ENCODING)
113 base = static_cast<WebCoreStringResource8*>(resource);
114 else
115 base = static_cast<WebCoreStringResource16*>(resource);
116 return StringTraits<StringType>::fromStringResource(base);
117 }
118 }
119
120 int length = v8String->Length();
121 if (UNLIKELY(!length))
122 return StringType("");
123
124 bool oneByte = v8String->ContainsOnlyOneByte();
125 StringType result(oneByte ? StringTraits<StringType>::template fromV8String<V8StringOneByteTrait>(v8String, length) : StringTraits<StringType>::template fromV8String<V8StringTwoBytesTrait>(v8String, length));
126
127 if (external != Externalize || !v8String->CanMakeExternal())
128 return result;
129
130 if (result.is8Bit()) {
131 WebCoreStringResource8* stringResource = new WebCoreStringResource8(result);
132 if (UNLIKELY(!v8String->MakeExternal(stringResource)))
133 delete stringResource;
134 } else {
135 WebCoreStringResource16* stringResource = new WebCoreStringResource16(result);
136 if (UNLIKELY(!v8String->MakeExternal(stringResource)))
137 delete stringResource;
138 }
139 return result;
140 }
141
142 // Explicitly instantiate the above template with the expected parameterizations,
143 // to ensure the compiler generates the code; otherwise link errors can result in GCC 4.4.
144 template String v8StringToWebCoreString<String>(v8::Handle<v8::String>, ExternalMode);
145 template AtomicString v8StringToWebCoreString<AtomicString>(v8::Handle<v8::String>, ExternalMode);
146
147 // Fast but non thread-safe version.
int32ToWebCoreStringFast(int value)148 String int32ToWebCoreStringFast(int value)
149 {
150 // Caching of small strings below is not thread safe: newly constructed AtomicString
151 // are not safely published.
152 ASSERT(isMainThread());
153
154 // Most numbers used are <= 100. Even if they aren't used there's very little cost in using the space.
155 const int kLowNumbers = 100;
156 DEFINE_STATIC_LOCAL(Vector<AtomicString>, lowNumbers, (kLowNumbers + 1));
157 String webCoreString;
158 if (0 <= value && value <= kLowNumbers) {
159 webCoreString = lowNumbers[value];
160 if (!webCoreString) {
161 AtomicString valueString = AtomicString::number(value);
162 lowNumbers[value] = valueString;
163 webCoreString = valueString;
164 }
165 } else
166 webCoreString = String::number(value);
167 return webCoreString;
168 }
169
int32ToWebCoreString(int value)170 String int32ToWebCoreString(int value)
171 {
172 // If we are on the main thread (this should always true for non-workers), call the faster one.
173 if (isMainThread())
174 return int32ToWebCoreStringFast(value);
175 return String::number(value);
176 }
177
178 } // namespace WebCore
179