Home | History | Annotate | Download | only in extensions 
      1 // Copyright 2010 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/extensions/externalize-string-extension.h"
      6 
      7 #include "src/api.h"
      8 #include "src/handles.h"
      9 #include "src/isolate.h"
     10 #include "src/objects-inl.h"
     11 
     12 namespace v8 {
     13 namespace internal {
     14 
     15 template <typename Char, typename Base>
     16 class SimpleStringResource : public Base {
     17  public:
     18   // Takes ownership of |data|.
     19   SimpleStringResource(Char* data, size_t length)
     20       : data_(data),
     21         length_(length) {}
     22 
     23   virtual ~SimpleStringResource() { delete[] data_; }
     24 
     25   virtual const Char* data() const { return data_; }
     26 
     27   virtual size_t length() const { return length_; }
     28 
     29  private:
     30   Char* const data_;
     31   const size_t length_;
     32 };
     33 
     34 
     35 typedef SimpleStringResource<char, v8::String::ExternalOneByteStringResource>
     36     SimpleOneByteStringResource;
     37 typedef SimpleStringResource<uc16, v8::String::ExternalStringResource>
     38     SimpleTwoByteStringResource;
     39 
     40 const char* const ExternalizeStringExtension::kSource =
     41     "native function externalizeString();"
     42     "native function isOneByteString();"
     43     "function x() { return 1; }";
     44 
     45 v8::Local<v8::FunctionTemplate>
     46 ExternalizeStringExtension::GetNativeFunctionTemplate(
     47     v8::Isolate* isolate, v8::Local<v8::String> str) {
     48   if (strcmp(*v8::String::Utf8Value(str), "externalizeString") == 0) {
     49     return v8::FunctionTemplate::New(isolate,
     50                                      ExternalizeStringExtension::Externalize);
     51   } else {
     52     DCHECK(strcmp(*v8::String::Utf8Value(str), "isOneByteString") == 0);
     53     return v8::FunctionTemplate::New(isolate,
     54                                      ExternalizeStringExtension::IsOneByte);
     55   }
     56 }
     57 
     58 
     59 void ExternalizeStringExtension::Externalize(
     60     const v8::FunctionCallbackInfo<v8::Value>& args) {
     61   if (args.Length() < 1 || !args[0]->IsString()) {
     62     args.GetIsolate()->ThrowException(
     63         v8::String::NewFromUtf8(
     64             args.GetIsolate(),
     65             "First parameter to externalizeString() must be a string.",
     66             NewStringType::kNormal).ToLocalChecked());
     67     return;
     68   }
     69   bool force_two_byte = false;
     70   if (args.Length() >= 2) {
     71     if (args[1]->IsBoolean()) {
     72       force_two_byte =
     73           args[1]
     74               ->BooleanValue(args.GetIsolate()->GetCurrentContext())
     75               .FromJust();
     76     } else {
     77       args.GetIsolate()->ThrowException(
     78           v8::String::NewFromUtf8(
     79               args.GetIsolate(),
     80               "Second parameter to externalizeString() must be a boolean.",
     81               NewStringType::kNormal).ToLocalChecked());
     82       return;
     83     }
     84   }
     85   bool result = false;
     86   Handle<String> string = Utils::OpenHandle(*args[0].As<v8::String>());
     87   if (string->IsExternalString()) {
     88     args.GetIsolate()->ThrowException(
     89         v8::String::NewFromUtf8(args.GetIsolate(),
     90                                 "externalizeString() can't externalize twice.",
     91                                 NewStringType::kNormal).ToLocalChecked());
     92     return;
     93   }
     94   if (string->IsOneByteRepresentation() && !force_two_byte) {
     95     uint8_t* data = new uint8_t[string->length()];
     96     String::WriteToFlat(*string, data, 0, string->length());
     97     SimpleOneByteStringResource* resource = new SimpleOneByteStringResource(
     98         reinterpret_cast<char*>(data), string->length());
     99     result = string->MakeExternal(resource);
    100     if (result) {
    101       i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
    102       isolate->heap()->RegisterExternalString(*string);
    103     }
    104     if (!result) delete resource;
    105   } else {
    106     uc16* data = new uc16[string->length()];
    107     String::WriteToFlat(*string, data, 0, string->length());
    108     SimpleTwoByteStringResource* resource = new SimpleTwoByteStringResource(
    109         data, string->length());
    110     result = string->MakeExternal(resource);
    111     if (result) {
    112       i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
    113       isolate->heap()->RegisterExternalString(*string);
    114     }
    115     if (!result) delete resource;
    116   }
    117   if (!result) {
    118     args.GetIsolate()->ThrowException(
    119         v8::String::NewFromUtf8(args.GetIsolate(),
    120                                 "externalizeString() failed.",
    121                                 NewStringType::kNormal).ToLocalChecked());
    122     return;
    123   }
    124 }
    125 
    126 
    127 void ExternalizeStringExtension::IsOneByte(
    128     const v8::FunctionCallbackInfo<v8::Value>& args) {
    129   if (args.Length() != 1 || !args[0]->IsString()) {
    130     args.GetIsolate()->ThrowException(
    131         v8::String::NewFromUtf8(
    132             args.GetIsolate(),
    133             "isOneByteString() requires a single string argument.",
    134             NewStringType::kNormal).ToLocalChecked());
    135     return;
    136   }
    137   bool is_one_byte =
    138       Utils::OpenHandle(*args[0].As<v8::String>())->IsOneByteRepresentation();
    139   args.GetReturnValue().Set(is_one_byte);
    140 }
    141 
    142 }  // namespace internal
    143 }  // namespace v8
    144