/* Copyright 2011 Google Inc. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package index import ( "bytes" "errors" "camlistore.org/pkg/blob" "camlistore.org/pkg/magic" "camlistore.org/pkg/schema" ) type BlobSniffer struct { br blob.Ref contents []byte written int64 meta *schema.Blob // or nil mimeType string camliType string } func NewBlobSniffer(ref blob.Ref) *BlobSniffer { if !ref.Valid() { panic("invalid ref") } return &BlobSniffer{br: ref} } func (sn *BlobSniffer) SchemaBlob() (meta *schema.Blob, ok bool) { return sn.meta, sn.meta != nil } func (sn *BlobSniffer) Write(d []byte) (int, error) { if !sn.br.Valid() { panic("write on sniffer with invalid blobref") } sn.written += int64(len(d)) if len(sn.contents) < schema.MaxSchemaBlobSize { n := schema.MaxSchemaBlobSize - len(sn.contents) if len(d) < n { n = len(d) } sn.contents = append(sn.contents, d[:n]...) } return len(d), nil } // Size returns the number of bytes written to the BlobSniffer. // It might be more than schema.MaxSchemaBlobSize. // See IsTruncated. func (sn *BlobSniffer) Size() int64 { return sn.written } // IsTruncated reports whether the BlobSniffer had more than // schema.MaxSchemaBlobSize bytes written to it. func (sn *BlobSniffer) IsTruncated() bool { return sn.written > schema.MaxSchemaBlobSize } // Body returns the bytes written to the BlobSniffer. func (sn *BlobSniffer) Body() ([]byte, error) { if sn.IsTruncated() { return nil, errors.New("index.Body: was truncated") } return sn.contents, nil } // MIMEType returns the sniffed blob's content-type or the empty string if unknown. // If the blob is a Camlistore schema metadata blob, the MIME type will be of // the form "application/json; camliType=foo". func (sn *BlobSniffer) MIMEType() string { return sn.mimeType } func (sn *BlobSniffer) CamliType() string { return sn.camliType } func (sn *BlobSniffer) Parse() { if sn.bufferIsCamliJSON() { sn.camliType = sn.meta.Type() sn.mimeType = "application/json; camliType=" + sn.camliType } else { sn.mimeType = magic.MIMEType(sn.contents) } } func (sn *BlobSniffer) bufferIsCamliJSON() bool { buf := sn.contents if !schema.LikelySchemaBlob(buf) { return false } blob, err := schema.BlobFromReader(sn.br, bytes.NewReader(buf)) if err != nil { return false } sn.meta = blob return true }