gitech

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// Copyright 2018 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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//go:build !gogit
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package git
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import (
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	"bufio"
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	"bytes"
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	"fmt"
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	"io"
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	"strconv"
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	"strings"
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	"code.gitea.io/gitea/modules/log"
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)
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// ParseTreeEntries parses the output of a `git ls-tree -l` command.
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func ParseTreeEntries(objectFormat ObjectFormat, data []byte) ([]*TreeEntry, error) {
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	return parseTreeEntries(objectFormat, data, nil)
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}
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var sepSpace = []byte{' '}
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func parseTreeEntries(objectFormat ObjectFormat, data []byte, ptree *Tree) ([]*TreeEntry, error) {
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	var err error
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	entries := make([]*TreeEntry, 0, bytes.Count(data, []byte{'\n'})+1)
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	for pos := 0; pos < len(data); {
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		// expect line to be of the form:
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		// <mode> <type> <sha> <space-padded-size>\t<filename>
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		// <mode> <type> <sha>\t<filename>
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		posEnd := bytes.IndexByte(data[pos:], '\n')
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		if posEnd == -1 {
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			posEnd = len(data)
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		} else {
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			posEnd += pos
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		}
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		line := data[pos:posEnd]
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		posTab := bytes.IndexByte(line, '\t')
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		if posTab == -1 {
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			return nil, fmt.Errorf("invalid ls-tree output (no tab): %q", line)
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		}
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		entry := new(TreeEntry)
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		entry.ptree = ptree
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		entryAttrs := line[:posTab]
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		entryName := line[posTab+1:]
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		entryMode, entryAttrs, _ := bytes.Cut(entryAttrs, sepSpace)
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		_ /* entryType */, entryAttrs, _ = bytes.Cut(entryAttrs, sepSpace) // the type is not used, the mode is enough to determine the type
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		entryObjectID, entryAttrs, _ := bytes.Cut(entryAttrs, sepSpace)
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		if len(entryAttrs) > 0 {
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			entrySize := entryAttrs // the last field is the space-padded-size
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			entry.size, _ = strconv.ParseInt(strings.TrimSpace(string(entrySize)), 10, 64)
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			entry.sized = true
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		}
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		switch string(entryMode) {
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		case "100644":
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			entry.entryMode = EntryModeBlob
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		case "100755":
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			entry.entryMode = EntryModeExec
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		case "120000":
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			entry.entryMode = EntryModeSymlink
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		case "160000":
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			entry.entryMode = EntryModeCommit
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		case "040000", "040755": // git uses 040000 for tree object, but some users may get 040755 for unknown reasons
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			entry.entryMode = EntryModeTree
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		default:
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			return nil, fmt.Errorf("unknown type: %v", string(entryMode))
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		}
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		entry.ID, err = NewIDFromString(string(entryObjectID))
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		if err != nil {
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			return nil, fmt.Errorf("invalid ls-tree output (invalid object id): %q, err: %w", line, err)
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		}
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		if len(entryName) > 0 && entryName[0] == '"' {
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			entry.name, err = strconv.Unquote(string(entryName))
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			if err != nil {
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				return nil, fmt.Errorf("invalid ls-tree output (invalid name): %q, err: %w", line, err)
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			}
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		} else {
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			entry.name = string(entryName)
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		}
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		pos = posEnd + 1
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		entries = append(entries, entry)
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	}
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	return entries, nil
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}
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func catBatchParseTreeEntries(objectFormat ObjectFormat, ptree *Tree, rd *bufio.Reader, sz int64) ([]*TreeEntry, error) {
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	fnameBuf := make([]byte, 4096)
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	modeBuf := make([]byte, 40)
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	shaBuf := make([]byte, objectFormat.FullLength())
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	entries := make([]*TreeEntry, 0, 10)
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loop:
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	for sz > 0 {
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		mode, fname, sha, count, err := ParseTreeLine(objectFormat, rd, modeBuf, fnameBuf, shaBuf)
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		if err != nil {
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			if err == io.EOF {
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				break loop
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			}
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			return nil, err
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		}
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		sz -= int64(count)
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		entry := new(TreeEntry)
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		entry.ptree = ptree
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		switch string(mode) {
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		case "100644":
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			entry.entryMode = EntryModeBlob
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		case "100755":
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			entry.entryMode = EntryModeExec
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		case "120000":
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			entry.entryMode = EntryModeSymlink
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		case "160000":
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			entry.entryMode = EntryModeCommit
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		case "40000", "40755": // git uses 40000 for tree object, but some users may get 40755 for unknown reasons
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			entry.entryMode = EntryModeTree
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		default:
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			log.Debug("Unknown mode: %v", string(mode))
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			return nil, fmt.Errorf("unknown mode: %v", string(mode))
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		}
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		entry.ID = objectFormat.MustID(sha)
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		entry.name = string(fname)
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		entries = append(entries, entry)
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	}
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	if _, err := rd.Discard(1); err != nil {
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		return entries, err
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	}
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	return entries, nil
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}
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