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