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Diffstat (limited to 'textproto/catblob.go')
-rw-r--r-- | textproto/catblob.go | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/textproto/catblob.go b/textproto/catblob.go new file mode 100644 index 0000000..6836689 --- /dev/null +++ b/textproto/catblob.go @@ -0,0 +1,106 @@ +// Copyright (C) 2017-2018 Luke Shumaker <lukeshu@lukeshu.com> +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU Affero General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Affero General Public License for more details. +// +// You should have received a copy of the GNU Affero General Public License +// along with this program. If not, see <https://www.gnu.org/licenses/>. + +package textproto + +import ( + "bufio" + "fmt" + "io" + "strconv" +) + +// CatBlobReader is a low-level parser of an fast-import auxiliary +// "cat-blob" stream. +type CatBlobReader struct { + r *bufio.Reader +} + +// NewCatBlobReader creates a new CatBlobReader parser. +func NewCatBlobReader(r io.Reader) *CatBlobReader { + return &CatBlobReader{ + r: bufio.NewReader(r), + } +} + +// ReadLine reads a response from the stream; with special handling +// for responses to "cat-blob" commands, which contain multiple +// newline characters. +func (cbr *CatBlobReader) ReadLine() (line string, err error) { + for len(line) <= 1 { + line, err = cbr.r.ReadString('\n') + if err != nil { + return + } + } + + // get-mark : <sha1> LF + // cat-blob : <sha1> SP 'blob' SP <size> LF + // <data> LF + // ls : <mode> SP ('blob' | 'tree' | 'commit') SP <dataref> HT <path> LF + // ls : 'missing' SP <path> LF + + // decide if we have a cat-blob result (return early if we don't) + if len(line) <= 46 || line[40:46] != " blob " { + return + } + for _, b := range line[:40] { + if !(('0' <= b && b <= '9') || ('a' <= b && b <= 'f')) { + return + } + } + // we have a cat-blob result + var size int + size, err = strconv.Atoi(line[46 : len(line)-1]) + if err != nil { + return + } + data := make([]byte, size+1) + _, err = io.ReadFull(cbr.r, data) + line += string(data) + return +} + +// CatBlobWriter is a low-level marshaller for an auxiliary cat-blob +// stream. +type CatBlobWriter struct { + w io.Writer +} + +// NewCatBlobWriter creates a new CatBlobWriter marshaller. +func NewCatBlobWriter(w io.Writer) *CatBlobWriter { + return &CatBlobWriter{ + w: w, + } +} + +// WriteLine writes a response (to a command OTHER THAN "cat-blob") to +// the stream; arguments are handled similarly to fmt.Println. +// +// Use WriteBlob instead to write responses to "cat-blob" commands. +func (cbw *CatBlobWriter) WriteLine(a ...interface{}) error { + _, err := fmt.Fprintln(cbw.w, a...) + return err +} + +// WriteBlob writes a response to a "cat-blob" command to the stream. +func (cbw *CatBlobWriter) WriteBlob(sha1 string, data string) error { + err := cbw.WriteLine(sha1, "blob", len(data)) + if err != nil { + return err + } + _, err = io.WriteString(cbw.w, data) + return err +} |