node-custom/src/node_buffer.h at master · BillBarnhill/node-custom · GitHub

History

132 lines (104 loc) · 4.98 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

// Copyright Joyent, Inc. and other Node contributors.

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef NODE_BUFFER_H_

#define NODE_BUFFER_H_

#include <node.h>

#include <node_object_wrap.h>

#include <v8.h>

#include <assert.h>

namespace node {

/* A buffer is a chunk of memory stored outside the V8 heap, mirrored by an

* object in javascript. The object is not totally opaque, one can access

* individual bytes with [] and slice it into substrings or sub-buffers

* without copying memory.

The C++ API for Buffer changed radically between v0.2 and v0.3, in fact

it was the reason for bumping the version. In v0.2 JavaScript Buffers and

C++ Buffers were in one-to-one correspondence via ObjectWrap. We found

that it was faster to expose the C++ Buffers to JavaScript as a

"SlowBuffer" which is used as a private backend to pure JavaScript

"Buffer" objects - a 'Buffer' in v0.3 might look like this:

{ _parent: s,

_offset: 520,

length: 5 }

Migrating code C++ Buffer code from v0.2 to v0.3 is difficult. Here are

some tips:

- buffer->data() calls should become Buffer::Data(buffer) calls.

- buffer->length() calls should become Buffer::Length(buffer) calls.

- There should not be any ObjectWrap::Unwrap<Buffer>() calls. You should

not be storing pointers to Buffer objects at all - as they are

now considered internal structures. Instead consider making a

JavaScript reference to the buffer.

See the source code node-png as an example of a module which successfully

compiles on both v0.2 and v0.3 while making heavy use of the C++ Buffer

API.

class Buffer : public ObjectWrap {

public:

static bool HasInstance(v8::Handle<v8::Value> val);

static inline char* Data(v8::Handle<v8::Object> obj) {

return (char*)obj->GetIndexedPropertiesExternalArrayData();

}

static inline char* Data(Buffer *b) {

return Buffer::Data(b->handle_);

}

static inline size_t Length(v8::Handle<v8::Object> obj) {

return (size_t)obj->GetIndexedPropertiesExternalArrayDataLength();

}

static inline size_t Length(Buffer *b) {

return Buffer::Length(b->handle_);

}

~Buffer();

typedef void (*free_callback)(char *data, void *hint);

// C++ API for constructing fast buffer

static v8::Handle<v8::Object> New(v8::Handle<v8::String> string);

static void Initialize(v8::Handle<v8::Object> target);

static Buffer* New(size_t length); // public constructor

static Buffer* New(char *data, size_t len); // public constructor

static Buffer* New(char *data, size_t length,

free_callback callback, void *hint); // public constructor

private:

static v8::Persistent<v8::FunctionTemplate> constructor_template;

static v8::Handle<v8::Value> New(const v8::Arguments &args);

static v8::Handle<v8::Value> BinarySlice(const v8::Arguments &args);

static v8::Handle<v8::Value> AsciiSlice(const v8::Arguments &args);

static v8::Handle<v8::Value> Base64Slice(const v8::Arguments &args);

static v8::Handle<v8::Value> Utf8Slice(const v8::Arguments &args);

static v8::Handle<v8::Value> Ucs2Slice(const v8::Arguments &args);

static v8::Handle<v8::Value> BinaryWrite(const v8::Arguments &args);

static v8::Handle<v8::Value> Base64Write(const v8::Arguments &args);

static v8::Handle<v8::Value> AsciiWrite(const v8::Arguments &args);

static v8::Handle<v8::Value> Utf8Write(const v8::Arguments &args);

static v8::Handle<v8::Value> Ucs2Write(const v8::Arguments &args);

static v8::Handle<v8::Value> ByteLength(const v8::Arguments &args);

static v8::Handle<v8::Value> MakeFastBuffer(const v8::Arguments &args);

static v8::Handle<v8::Value> Fill(const v8::Arguments &args);

static v8::Handle<v8::Value> Copy(const v8::Arguments &args);

Buffer(v8::Handle<v8::Object> wrapper, size_t length);

void Replace(char *data, size_t length, free_callback callback, void *hint);

size_t length_;

char* data_;

free_callback callback_;

void* callback_hint_;

};

} // namespace node buffer

#endif // NODE_BUFFER_H_

node-custom/src/node_buffer.h at master · BillBarnhill/node-custom · GitHub

Expand file tree

Breadcrumbs

node_buffer.h

Latest commit

History

Breadcrumbs

node_buffer.h

File metadata and controls