diff options
Diffstat (limited to 'vendor/gopkg.in/mgo.v2/gridfs.go')
| -rw-r--r-- | vendor/gopkg.in/mgo.v2/gridfs.go | 761 |
1 files changed, 761 insertions, 0 deletions
diff --git a/vendor/gopkg.in/mgo.v2/gridfs.go b/vendor/gopkg.in/mgo.v2/gridfs.go new file mode 100644 index 0000000..2ac4ff5 --- /dev/null +++ b/vendor/gopkg.in/mgo.v2/gridfs.go @@ -0,0 +1,761 @@ +// mgo - MongoDB driver for Go +// +// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net> +// +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this +// list of conditions and the following disclaimer. +// 2. Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR +// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +package mgo + +import ( + "crypto/md5" + "encoding/hex" + "errors" + "hash" + "io" + "os" + "sync" + "time" + + "gopkg.in/mgo.v2/bson" +) + +type GridFS struct { + Files *Collection + Chunks *Collection +} + +type gfsFileMode int + +const ( + gfsClosed gfsFileMode = 0 + gfsReading gfsFileMode = 1 + gfsWriting gfsFileMode = 2 +) + +type GridFile struct { + m sync.Mutex + c sync.Cond + gfs *GridFS + mode gfsFileMode + err error + + chunk int + offset int64 + + wpending int + wbuf []byte + wsum hash.Hash + + rbuf []byte + rcache *gfsCachedChunk + + doc gfsFile +} + +type gfsFile struct { + Id interface{} "_id" + ChunkSize int "chunkSize" + UploadDate time.Time "uploadDate" + Length int64 ",minsize" + MD5 string + Filename string ",omitempty" + ContentType string "contentType,omitempty" + Metadata *bson.Raw ",omitempty" +} + +type gfsChunk struct { + Id interface{} "_id" + FilesId interface{} "files_id" + N int + Data []byte +} + +type gfsCachedChunk struct { + wait sync.Mutex + n int + data []byte + err error +} + +func newGridFS(db *Database, prefix string) *GridFS { + return &GridFS{db.C(prefix + ".files"), db.C(prefix + ".chunks")} +} + +func (gfs *GridFS) newFile() *GridFile { + file := &GridFile{gfs: gfs} + file.c.L = &file.m + //runtime.SetFinalizer(file, finalizeFile) + return file +} + +func finalizeFile(file *GridFile) { + file.Close() +} + +// 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 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: 255 * 1024, Filename: name} + return +} + +// OpenId returns the file with the provided id, for reading. +// If the file isn't found, err will be set to mgo.ErrNotFound. +// +// 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. +// +// The following example will print the first 8192 bytes from the file: +// +// func check(err error) { +// if err != nil { +// panic(err.String()) +// } +// } +// file, err := db.GridFS("fs").OpenId(objid) +// check(err) +// b := make([]byte, 8192) +// n, err := file.Read(b) +// check(err) +// fmt.Println(string(b)) +// check(err) +// err = file.Close() +// check(err) +// fmt.Printf("%d bytes read\n", n) +// +// The io.Reader interface is implemented by *GridFile and may be used to +// deal with it. As an example, the following snippet will dump the whole +// file into the standard output: +// +// file, err := db.GridFS("fs").OpenId(objid) +// check(err) +// err = io.Copy(os.Stdout, file) +// check(err) +// err = file.Close() +// check(err) +// +func (gfs *GridFS) OpenId(id interface{}) (file *GridFile, err error) { + var doc gfsFile + err = gfs.Files.Find(bson.M{"_id": id}).One(&doc) + if err != nil { + return + } + file = gfs.newFile() + file.mode = gfsReading + file.doc = doc + return +} + +// Open returns the most recently uploaded file with the provided +// name, for reading. If the file isn't found, err will be set +// to mgo.ErrNotFound. +// +// 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. +// +// The following example will print the first 8192 bytes from the file: +// +// file, err := db.GridFS("fs").Open("myfile.txt") +// check(err) +// b := make([]byte, 8192) +// n, err := file.Read(b) +// check(err) +// fmt.Println(string(b)) +// check(err) +// err = file.Close() +// check(err) +// fmt.Printf("%d bytes read\n", n) +// +// The io.Reader interface is implemented by *GridFile and may be used to +// deal with it. As an example, the following snippet will dump the whole +// file into the standard output: +// +// file, err := db.GridFS("fs").Open("myfile.txt") +// check(err) +// err = io.Copy(os.Stdout, file) +// check(err) +// err = file.Close() +// check(err) +// +func (gfs *GridFS) Open(name string) (file *GridFile, err error) { + var doc gfsFile + err = gfs.Files.Find(bson.M{"filename": name}).Sort("-uploadDate").One(&doc) + if err != nil { + return + } + file = gfs.newFile() + file.mode = gfsReading + file.doc = doc + return +} + +// OpenNext opens the next file from iter for reading, sets *file to it, +// and returns true on the success case. If no more documents are available +// on iter or an error occurred, *file is set to nil and the result is false. +// Errors will be available via iter.Err(). +// +// The iter parameter must be an iterator on the GridFS files collection. +// Using the GridFS.Find method is an easy way to obtain such an iterator, +// but any iterator on the collection will work. +// +// If the provided *file is non-nil, OpenNext will close it before attempting +// to iterate to the next element. This means that in a loop one only +// has to worry about closing files when breaking out of the loop early +// (break, return, or panic). +// +// For example: +// +// gfs := db.GridFS("fs") +// query := gfs.Find(nil).Sort("filename") +// iter := query.Iter() +// var f *mgo.GridFile +// for gfs.OpenNext(iter, &f) { +// fmt.Printf("Filename: %s\n", f.Name()) +// } +// if iter.Close() != nil { +// panic(iter.Close()) +// } +// +func (gfs *GridFS) OpenNext(iter *Iter, file **GridFile) bool { + if *file != nil { + // Ignoring the error here shouldn't be a big deal + // as we're reading the file and the loop iteration + // for this file is finished. + _ = (*file).Close() + } + var doc gfsFile + if !iter.Next(&doc) { + *file = nil + return false + } + f := gfs.newFile() + f.mode = gfsReading + f.doc = doc + *file = f + return true +} + +// Find runs query on GridFS's files collection and returns +// the resulting Query. +// +// This logic: +// +// gfs := db.GridFS("fs") +// iter := gfs.Find(nil).Iter() +// +// Is equivalent to: +// +// files := db.C("fs" + ".files") +// iter := files.Find(nil).Iter() +// +func (gfs *GridFS) Find(query interface{}) *Query { + return gfs.Files.Find(query) +} + +// RemoveId deletes the file with the provided id from the GridFS. +func (gfs *GridFS) RemoveId(id interface{}) error { + err := gfs.Files.Remove(bson.M{"_id": id}) + if err != nil { + return err + } + _, err = gfs.Chunks.RemoveAll(bson.D{{"files_id", id}}) + return err +} + +type gfsDocId struct { + Id interface{} "_id" +} + +// Remove deletes all files with the provided name from the GridFS. +func (gfs *GridFS) Remove(name string) (err error) { + iter := gfs.Files.Find(bson.M{"filename": name}).Select(bson.M{"_id": 1}).Iter() + var doc gfsDocId + for iter.Next(&doc) { + if e := gfs.RemoveId(doc.Id); e != nil { + err = e + } + } + if err == nil { + err = iter.Close() + } + return err +} + +func (file *GridFile) assertMode(mode gfsFileMode) { + switch file.mode { + case mode: + return + case gfsWriting: + panic("GridFile is open for writing") + case gfsReading: + panic("GridFile is open for reading") + case gfsClosed: + panic("GridFile is closed") + default: + panic("internal error: missing GridFile mode") + } +} + +// SetChunkSize sets size of saved chunks. Once the file is written to, it +// will be split in blocks of that size and each block saved into an +// independent chunk document. The default chunk size is 256kb. +// +// It is a runtime error to call this function once the file has started +// being written to. +func (file *GridFile) SetChunkSize(bytes int) { + file.assertMode(gfsWriting) + debugf("GridFile %p: setting chunk size to %d", file, bytes) + file.m.Lock() + file.doc.ChunkSize = bytes + file.m.Unlock() +} + +// Id returns the current file Id. +func (file *GridFile) Id() interface{} { + return file.doc.Id +} + +// SetId changes the current file Id. +// +// It is a runtime error to call this function once the file has started +// being written to, or when the file is not open for writing. +func (file *GridFile) SetId(id interface{}) { + file.assertMode(gfsWriting) + file.m.Lock() + file.doc.Id = id + file.m.Unlock() +} + +// Name returns the optional file name. An empty string will be returned +// in case it is unset. +func (file *GridFile) Name() string { + return file.doc.Filename +} + +// SetName changes the optional file name. An empty string may be used to +// unset it. +// +// It is a runtime error to call this function when the file is not open +// for writing. +func (file *GridFile) SetName(name string) { + file.assertMode(gfsWriting) + file.m.Lock() + file.doc.Filename = name + file.m.Unlock() +} + +// ContentType returns the optional file content type. An empty string will be +// returned in case it is unset. +func (file *GridFile) ContentType() string { + return file.doc.ContentType +} + +// ContentType changes the optional file content type. An empty string may be +// used to unset it. +// +// It is a runtime error to call this function when the file is not open +// for writing. +func (file *GridFile) SetContentType(ctype string) { + file.assertMode(gfsWriting) + file.m.Lock() + file.doc.ContentType = ctype + file.m.Unlock() +} + +// GetMeta unmarshals the optional "metadata" field associated with the +// file into the result parameter. The meaning of keys under that field +// is user-defined. For example: +// +// result := struct{ INode int }{} +// err = file.GetMeta(&result) +// if err != nil { +// panic(err.String()) +// } +// fmt.Printf("inode: %d\n", result.INode) +// +func (file *GridFile) GetMeta(result interface{}) (err error) { + file.m.Lock() + if file.doc.Metadata != nil { + err = bson.Unmarshal(file.doc.Metadata.Data, result) + } + file.m.Unlock() + return +} + +// SetMeta changes the optional "metadata" field associated with the +// file. The meaning of keys under that field is user-defined. +// For example: +// +// file.SetMeta(bson.M{"inode": inode}) +// +// It is a runtime error to call this function when the file is not open +// for writing. +func (file *GridFile) SetMeta(metadata interface{}) { + file.assertMode(gfsWriting) + data, err := bson.Marshal(metadata) + file.m.Lock() + if err != nil && file.err == nil { + file.err = err + } else { + file.doc.Metadata = &bson.Raw{Data: data} + } + file.m.Unlock() +} + +// Size returns the file size in bytes. +func (file *GridFile) Size() (bytes int64) { + file.m.Lock() + bytes = file.doc.Length + file.m.Unlock() + return +} + +// MD5 returns the file MD5 as a hex-encoded string. +func (file *GridFile) MD5() (md5 string) { + return file.doc.MD5 +} + +// UploadDate returns the file upload time. +func (file *GridFile) UploadDate() time.Time { + return file.doc.UploadDate +} + +// SetUploadDate changes the file upload time. +// +// It is a runtime error to call this function when the file is not open +// for writing. +func (file *GridFile) SetUploadDate(t time.Time) { + file.assertMode(gfsWriting) + file.m.Lock() + file.doc.UploadDate = t + file.m.Unlock() +} + +// Close flushes any pending changes in case the file is being written +// to, waits for any background operations to finish, and closes the file. +// +// 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. +func (file *GridFile) Close() (err error) { + file.m.Lock() + defer file.m.Unlock() + if file.mode == gfsWriting { + if len(file.wbuf) > 0 && file.err == nil { + file.insertChunk(file.wbuf) + file.wbuf = file.wbuf[0:0] + } + file.completeWrite() + } else if file.mode == gfsReading && file.rcache != nil { + file.rcache.wait.Lock() + file.rcache = nil + } + file.mode = gfsClosed + debugf("GridFile %p: closed", file) + return file.err +} + +func (file *GridFile) completeWrite() { + for file.wpending > 0 { + debugf("GridFile %p: waiting for %d pending chunks to complete file write", file, file.wpending) + file.c.Wait() + } + if file.err == nil { + hexsum := hex.EncodeToString(file.wsum.Sum(nil)) + if file.doc.UploadDate.IsZero() { + file.doc.UploadDate = bson.Now() + } + file.doc.MD5 = hexsum + file.err = file.gfs.Files.Insert(file.doc) + } + if file.err != nil { + file.gfs.Chunks.RemoveAll(bson.D{{"files_id", file.doc.Id}}) + } + if file.err == nil { + index := Index{ + Key: []string{"files_id", "n"}, + Unique: true, + } + file.err = file.gfs.Chunks.EnsureIndex(index) + } +} + +// Abort cancels an in-progress write, preventing the file from being +// automically created and ensuring previously written chunks are +// removed when the file is closed. +// +// It is a runtime error to call Abort when the file was not opened +// for writing. +func (file *GridFile) Abort() { + if file.mode != gfsWriting { + panic("file.Abort must be called on file opened for writing") + } + file.err = errors.New("write aborted") +} + +// Write writes the provided data to the file and returns the +// number of bytes written and an error in case something +// wrong happened. +// +// The file will internally cache the data so that all but the last +// chunk sent to the database have the size defined by SetChunkSize. +// This also means that errors may be deferred until a future call +// to Write or Close. +// +// The parameters and behavior of this function turn the file +// into an io.Writer. +func (file *GridFile) Write(data []byte) (n int, err error) { + file.assertMode(gfsWriting) + file.m.Lock() + debugf("GridFile %p: writing %d bytes", file, len(data)) + defer file.m.Unlock() + + if file.err != nil { + return 0, file.err + } + + n = len(data) + file.doc.Length += int64(n) + chunkSize := file.doc.ChunkSize + + if len(file.wbuf)+len(data) < chunkSize { + file.wbuf = append(file.wbuf, data...) + return + } + + // First, flush file.wbuf complementing with data. + if len(file.wbuf) > 0 { + missing := chunkSize - len(file.wbuf) + if missing > len(data) { + missing = len(data) + } + file.wbuf = append(file.wbuf, data[:missing]...) + data = data[missing:] + file.insertChunk(file.wbuf) + file.wbuf = file.wbuf[0:0] + } + + // Then, flush all chunks from data without copying. + for len(data) > chunkSize { + size := chunkSize + if size > len(data) { + size = len(data) + } + file.insertChunk(data[:size]) + data = data[size:] + } + + // And append the rest for a future call. + file.wbuf = append(file.wbuf, data...) + + return n, file.err +} + +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() + }() +} + +// Seek sets the offset for the next Read or Write on file to +// offset, interpreted according to whence: 0 means relative to +// the origin of the file, 1 means relative to the current offset, +// and 2 means relative to the end. It returns the new offset and +// an error, if any. +func (file *GridFile) Seek(offset int64, whence int) (pos int64, err error) { + file.m.Lock() + debugf("GridFile %p: seeking for %s (whence=%d)", file, offset, whence) + defer file.m.Unlock() + switch whence { + case os.SEEK_SET: + case os.SEEK_CUR: + offset += file.offset + case os.SEEK_END: + offset += file.doc.Length + default: + panic("unsupported whence value") + } + if offset > file.doc.Length { + return file.offset, errors.New("seek past end of file") + } + if offset == file.doc.Length { + // If we're seeking to the end of the file, + // no need to read anything. This enables + // a client to find the size of the file using only the + // io.ReadSeeker interface with low overhead. + file.offset = offset + return file.offset, nil + } + chunk := int(offset / int64(file.doc.ChunkSize)) + if chunk+1 == file.chunk && offset >= file.offset { + file.rbuf = file.rbuf[int(offset-file.offset):] + file.offset = offset + return file.offset, nil + } + file.offset = offset + file.chunk = chunk + file.rbuf = nil + file.rbuf, err = file.getChunk() + if err == nil { + file.rbuf = file.rbuf[int(file.offset-int64(chunk)*int64(file.doc.ChunkSize)):] + } + return file.offset, err +} + +// Read reads into b the next available data from the file and +// returns the number of bytes written and an error in case +// something wrong happened. At the end of the file, n will +// be zero and err will be set to io.EOF. +// +// The parameters and behavior of this function turn the file +// into an io.Reader. +func (file *GridFile) Read(b []byte) (n int, err error) { + file.assertMode(gfsReading) + file.m.Lock() + debugf("GridFile %p: reading at offset %d into buffer of length %d", file, file.offset, len(b)) + defer file.m.Unlock() + if file.offset == file.doc.Length { + return 0, io.EOF + } + for err == nil { + i := copy(b, file.rbuf) + n += i + file.offset += int64(i) + file.rbuf = file.rbuf[i:] + if i == len(b) || file.offset == file.doc.Length { + break + } + b = b[i:] + file.rbuf, err = file.getChunk() + } + return n, err +} + +func (file *GridFile) getChunk() (data []byte, err error) { + cache := file.rcache + file.rcache = nil + if cache != nil && cache.n == file.chunk { + debugf("GridFile %p: Getting chunk %d from cache", file, file.chunk) + cache.wait.Lock() + data, err = cache.data, cache.err + } else { + debugf("GridFile %p: Fetching chunk %d", file, file.chunk) + var doc gfsChunk + err = file.gfs.Chunks.Find(bson.D{{"files_id", file.doc.Id}, {"n", file.chunk}}).One(&doc) + data = doc.Data + } + file.chunk++ + if int64(file.chunk)*int64(file.doc.ChunkSize) < file.doc.Length { + // Read the next one in background. + cache = &gfsCachedChunk{n: file.chunk} + cache.wait.Lock() + debugf("GridFile %p: Scheduling chunk %d for background caching", file, file.chunk) + // Clone the session to avoid having it closed in between. + chunks := file.gfs.Chunks + session := chunks.Database.Session.Clone() + go func(id interface{}, n int) { + defer session.Close() + chunks = chunks.With(session) + var doc gfsChunk + cache.err = chunks.Find(bson.D{{"files_id", id}, {"n", n}}).One(&doc) + cache.data = doc.Data + cache.wait.Unlock() + }(file.doc.Id, file.chunk) + file.rcache = cache + } + debugf("Returning err: %#v", err) + return +} |