| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You 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 git |
| |
| import ( |
| "bufio" |
| "bytes" |
| "errors" |
| "fmt" |
| "strings" |
| ) |
| |
| const ( |
| // packedRefsHeader is the head for the `packed-refs` file |
| // based on https://github.com/git/git/blob/master/refs/packed-backend.c#LL1084C41-L1084C41 |
| packedRefsHeader = "# pack-refs with: peeled fully-peeled sorted " |
| tagRefPrefix = "refs/tags/" |
| originBranchRefPrefix = "refs/remotes/origin/" |
| unpeeledRefPrefix = '^' |
| ) |
| |
| // parsePackedRefs reads a `packed-refs` file, returning the packed branches and tags |
| func parsePackedRefs(data []byte) ( |
| map[string]Hash, // branches |
| map[string]Hash, // tags |
| error, |
| ) { |
| var ( |
| packedBranches = map[string]Hash{} |
| packedTags = map[string]Hash{} |
| ) |
| /* |
| data is in the format |
| <packedRefsHeader>\n |
| repeated: |
| <hash><space><ref>\n |
| (optional for tags if unpeeled)^<hash>\n |
| |
| for branches, the hash is the commit object |
| for tags, the hash is the tag object; the following line is the commit hash |
| */ |
| var lines []string |
| scanner := bufio.NewScanner(bytes.NewReader(data)) |
| for scanner.Scan() { |
| lines = append(lines, scanner.Text()) |
| } |
| if scanner.Err() != nil { |
| return nil, nil, scanner.Err() |
| } |
| for i := 0; i < len(lines); i++ { |
| line := lines[i] |
| if strings.HasPrefix(line, "#") { |
| // Git tells us the way that these refs are packed. In theory the refs |
| // may be packed in different ways, but as of today's writing, they are |
| // always packed fully-peeled. |
| // |
| // The comment should match `packedRefsHeader`. We can safely skip this comment if so. |
| if line != packedRefsHeader { |
| return nil, nil, fmt.Errorf("unknown packed-refs header: %q", line) |
| } |
| continue |
| } |
| hashHex, ref, found := strings.Cut(line, " ") |
| if !found { |
| return nil, nil, errors.New("invalid packed-refs file") |
| } |
| hash, err := parseHashFromHex(hashHex) |
| if err != nil { |
| return nil, nil, err |
| } |
| if strings.HasPrefix(ref, originBranchRefPrefix) { |
| branchName := strings.TrimPrefix(ref, originBranchRefPrefix) |
| packedBranches[branchName] = hash |
| } else if strings.HasPrefix(ref, tagRefPrefix) { |
| tagName := strings.TrimPrefix(ref, tagRefPrefix) |
| // We're looking at a tag. If the tag is annotated, the next line is our actual |
| // commit hash, prefixed with '^'. If not, the already read hash is our commit hash. |
| // We need to look ahead to see the next line. |
| if len(lines) > i+1 && lines[i+1][0] == unpeeledRefPrefix { |
| // We have an annotated tag that's been peeled. Let's read it. |
| i++ |
| nextLine := lines[i] |
| nextLine = strings.TrimPrefix(nextLine, string(unpeeledRefPrefix)) |
| hash, err = parseHashFromHex(nextLine) |
| if err != nil { |
| return nil, nil, err |
| } |
| } |
| packedTags[tagName] = hash |
| } |
| // We ignore all kinds of refs. |
| } |
| return packedBranches, packedTags, nil |
| } |