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Code Issues Releases Activity

Implement fs.read() for buffers

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This commit is contained in:
Ryan Dahl 2010-04-30 18:36:36 -07:00
parent 8d1f1186ca
commit 692f580a07
1 changed files with 133 additions and 32 deletions
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165
src/node_file.cc
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@ -89,11 +89,18 @@ static int After(eio_req *req) {
case EIO_READ:
{
argc = 3;
Local<Object> obj = Local<Object>::New(*callback);
Local<Value> enc_val = obj->GetHiddenValue(encoding_symbol);
argv[1] = Encode(req->ptr2, req->result, ParseEncoding(enc_val));
argv[2] = Integer::New(req->result);
if (req->int3) {
// legacy interface
Local<Object> obj = Local<Object>::New(*callback);
Local<Value> enc_val = obj->GetHiddenValue(encoding_symbol);
argv[1] = Encode(req->ptr2, req->result, ParseEncoding(enc_val));
argv[2] = Integer::New(req->result);
argc = 3;
} else {
// Buffer interface
argv[1] = Integer::New(req->result);
argc = 2;
}
break;
}
@ -556,55 +563,149 @@ static Handle<Value> Write(const Arguments& args) {
return Undefined();
} else {
if (pos < 0) {
written = write(fd, buf, len);
if (legacy) {
if (pos < 0) {
written = write(fd, buf, len);
} else {
written = pwrite(fd, buf, len, pos);
}
if (written < 0) return ThrowException(ErrnoException(errno));
return scope.Close(Integer::New(written));
} else {
written = pwrite(fd, buf, len, pos);
assert(0 && "fs.writeSync() with buffers is not yet supported");
}
if (written < 0) return ThrowException(ErrnoException(errno));
return scope.Close(Integer::New(written));
}
}
/* fs.read(fd, length, position, encoding)
/*
* Wrapper for read(2).
*
* fs.read(fd, buffer, offset, length, position)
*
* 0 fd integer. file descriptor
* 1 buffer instance of Buffer
* 2 offset integer. offset to start reading into inside buffer
* 3 length integer. length to read
* 4 position file position - null for current position
*
* - OR -
*
* fs.read(fd, length, position, encoding)
*
* 0 fd integer. file descriptor
* 1 length integer. length to read
* 2 position if integer, position to read from in the file.
* if null, read from the current position
* 3 encoding
*
*/
static Handle<Value> Read(const Arguments& args) {
HandleScope scope;
if (args.Length() < 2 || !args[0]->IsInt32() || !args[1]->IsNumber()) {
if (args.Length() < 2 || !args[0]->IsInt32()) {
return THROW_BAD_ARGS;
}
int fd = args[0]->Int32Value();
size_t len = args[1]->IntegerValue();
off_t offset = args[2]->IsNumber() ? args[2]->IntegerValue() : -1;
enum encoding encoding = ParseEncoding(args[3]);
if (args[4]->IsFunction()) {
Local<Object> obj = args[4]->ToObject();
obj->SetHiddenValue(encoding_symbol, args[3]);
ASYNC_CALL(read, args[4], fd, NULL, len, offset)
} else {
#define READ_BUF_LEN (16*1024)
char *buf[READ_BUF_LEN];
ssize_t ret;
if (offset < 0) {
ret = read(fd, buf, MIN(len, READ_BUF_LEN));
} else {
ret = pread(fd, buf, MIN(len, READ_BUF_LEN), offset);
Local<Value> cb;
bool legacy;
size_t len;
ssize_t pos;
enum encoding encoding;
char * buf = NULL;
if (Buffer::HasInstance(args[1])) {
legacy = false;
// 0 fd integer. file descriptor
// 1 buffer instance of Buffer
// 2 offset integer. offset to start reading into inside buffer
// 3 length integer. length to read
// 4 position file position - null for current position
Buffer * buffer = ObjectWrap::Unwrap<Buffer>(args[1]->ToObject());
size_t off = args[2]->Int32Value();
if (off >= buffer->length()) {
return ThrowException(Exception::Error(
String::New("Offset is out of bounds")));
}
len = args[3]->Int32Value();
if (off + len > buffer->length()) {
return ThrowException(Exception::Error(
String::New("Length is extends beyond buffer")));
}
pos = args[4]->IsNumber() ? args[4]->IntegerValue() : -1;
buf = (char*)buffer->data() + off;
cb = args[5];
} else {
legacy = true;
// 0 fd integer. file descriptor
// 1 length integer. length to read
// 2 position if integer, position to read from in the file.
// if null, read from the current position
// 3 encoding
len = args[1]->IntegerValue();
pos = args[2]->IsNumber() ? args[2]->IntegerValue() : -1;
encoding = ParseEncoding(args[3]);
buf = NULL; // libeio will allocate and free it.
cb = args[4];
}
if (cb->IsFunction()) {
// WARNING: HACK AGAIN, PROCEED WITH CAUTION
// Normally here I would do
// ASYNC_CALL(read, args[4], fd, NULL, len, offset)
// but I'm trying to support a legacy interface where it's acceptable to
// return a string in the callback. As well as a new Buffer interface
// which reads data into a user supplied buffer.
// Set the encoding on the callback
if (legacy) {
Local<Object> obj = cb->ToObject();
obj->SetHiddenValue(encoding_symbol, args[3]);
}
if (legacy) assert(buf == NULL);
eio_req *req = eio_read(fd, buf, len, pos,
EIO_PRI_DEFAULT,
After,
cb_persist(cb));
assert(req);
req->int3 = legacy ? 1 : 0;
ev_ref(EV_DEFAULT_UC);
return Undefined();
} else {
if (legacy) {
#define READ_BUF_LEN (16*1024)
char buf[READ_BUF_LEN];
ssize_t ret;
if (pos < 0) {
ret = read(fd, buf, MIN(len, READ_BUF_LEN));
} else {
ret = pread(fd, buf, MIN(len, READ_BUF_LEN), pos);
}
if (ret < 0) return ThrowException(ErrnoException(errno));
Local<Array> a = Array::New(2);
a->Set(Integer::New(0), Encode(buf, ret, encoding));
a->Set(Integer::New(1), Integer::New(ret));
return scope.Close(a);
} else {
assert(0 && "fs.readSync() with buffers is not support yet");
}
if (ret < 0) return ThrowException(ErrnoException(errno));
Local<Array> a = Array::New(2);
a->Set(Integer::New(0), Encode(buf, ret, encoding));
a->Set(Integer::New(1), Integer::New(ret));
return scope.Close(a);
}
}