Example #1
0
// Create creates a new file with the provided name in the GridFS.  If the file
// name already exists, a new version will be inserted with an up-to-date
// uploadDate that will cause it to be atomically visible to the Open and
// OpenId methods.  If the file name is not important, an empty name may be
// provided and the file Id used instead.
//
// It's important to Close files whether they are being written to
// or read from, and to check the err result to ensure the operation
// completed successfully.
//
// A simple example inserting a new file:
//
//     func check(err os.Error) {
//         if err != nil {
//             panic(err.String())
//         }
//     }
//     file, err := db.GridFS("fs").Create("myfile.txt")
//     check(err)
//     n, err := file.Write([]byte("Hello world!")
//     check(err)
//     err = file.Close()
//     check(err)
//     fmt.Printf("%d bytes written\n", n)
//
// The io.Writer interface is implemented by *GridFile and may be used to
// help on the file creation.  For example:
//
//     file, err := db.GridFS("fs").Create("myfile.txt")
//     check(err)
//     messages, err := os.Open("/var/log/messages")
//     check(err)
//     defer messages.Close()
//     err = io.Copy(file, messages)
//     check(err)
//     err = file.Close()
//     check(err)
//
func (gfs *GridFS) Create(name string) (file *GridFile, err error) {
	file = gfs.newFile()
	file.mode = gfsWriting
	file.wsum = md5.New()
	file.doc = gfsFile{Id: bson.NewObjectId(), ChunkSize: 256 * 1024, Filename: name}
	return
}
Example #2
0
func (file *GridFile) insertChunk(data []byte) {
	n := file.chunk
	file.chunk++
	debugf("GridFile %p: adding to checksum: %q", file, string(data))
	file.wsum.Write(data)

	for file.doc.ChunkSize*file.wpending >= 1024*1024 {
		// Hold on.. we got a MB pending.
		file.c.Wait()
		if file.err != nil {
			return
		}
	}

	file.wpending++

	debugf("GridFile %p: inserting chunk %d with %d bytes", file, n, len(data))

	// We may not own the memory of data, so rather than
	// simply copying it, we'll marshal the document ahead of time.
	data, err := bson.Marshal(gfsChunk{bson.NewObjectId(), file.doc.Id, n, data})
	if err != nil {
		file.err = err
		return
	}

	go func() {
		err := file.gfs.Chunks.Insert(bson.Raw{Data: data})
		file.m.Lock()
		file.wpending--
		if err != nil && file.err == nil {
			file.err = err
		}
		file.c.Broadcast()
		file.m.Unlock()
	}()
}