feat(third_party): Check in git-appraise r/10

1 files changed, 266 insertions, 0 deletions

diff --git a/third_party/go/git-appraise/review/comment/comment.go b/third_party/go/git-appraise/review/comment/comment.go
new file mode 100644
index 000000000000..b1dea49c13e4
--- /dev/null
+++ b/third_party/go/git-appraise/review/comment/comment.go
@@ -0,0 +1,266 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+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 comment defines the internal representation of a review comment.
+package comment
+
+import (
+	"crypto/sha1"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/git-appraise/repository"
+	"github.com/google/git-appraise/review/gpg"
+)
+
+// Ref defines the git-notes ref that we expect to contain review comments.
+const Ref = "refs/notes/devtools/discuss"
+
+// FormatVersion defines the latest version of the comment format supported by the tool.
+const FormatVersion = 0
+
+// ErrInvalidRange inidcates an error during parsing of a user-defined file
+// range
+var ErrInvalidRange = errors.New("invalid file location range. The required form is StartLine[+StartColumn][:EndLine[+EndColumn]]. The first line in a file is considered to be line 1")
+
+// Range represents the range of text that is under discussion.
+type Range struct {
+	StartLine   uint32 `json:"startLine"`
+	StartColumn uint32 `json:"startColumn,omitempty"`
+	EndLine     uint32 `json:"endLine,omitempty"`
+	EndColumn   uint32 `json:"endColumn,omitempty"`
+}
+
+// Location represents the location of a comment within a commit.
+type Location struct {
+	Commit string `json:"commit,omitempty"`
+	// If the path is omitted, then the comment applies to the entire commit.
+	Path string `json:"path,omitempty"`
+	// If the range is omitted, then the location represents an entire file.
+	Range *Range `json:"range,omitempty"`
+}
+
+// Check verifies that this location is valid in the provided
+// repository.
+func (location *Location) Check(repo repository.Repo) error {
+	contents, err := repo.Show(location.Commit, location.Path)
+	if err != nil {
+		return err
+	}
+	lines := strings.Split(contents, "\n")
+	if location.Range.StartLine > uint32(len(lines)) {
+		return fmt.Errorf("Line number %d does not exist in file %q",
+			location.Range.StartLine,
+			location.Path)
+	}
+	if location.Range.StartColumn != 0 &&
+		location.Range.StartColumn > uint32(len(lines[location.Range.StartLine-1])) {
+		return fmt.Errorf("Line %d in %q is too short for column %d",
+			location.Range.StartLine,
+			location.Path,
+			location.Range.StartColumn)
+	}
+	if location.Range.EndLine != 0 &&
+		location.Range.EndLine > uint32(len(lines)) {
+		return fmt.Errorf("End line number %d does not exist in file %q",
+			location.Range.EndLine,
+			location.Path)
+	}
+	if location.Range.EndColumn != 0 &&
+		location.Range.EndColumn > uint32(len(lines[location.Range.EndLine-1])) {
+		return fmt.Errorf("End line %d in %q is too short for column %d",
+			location.Range.EndLine,
+			location.Path,
+			location.Range.EndColumn)
+	}
+	return nil
+}
+
+// Comment represents a review comment, and can occur in any of the following contexts:
+// 1. As a comment on an entire commit.
+// 2. As a comment about a specific file in a commit.
+// 3. As a comment about a specific line in a commit.
+// 4. As a response to another comment.
+type Comment struct {
+	// Timestamp and Author are optimizations that allows us to display comment threads
+	// without having to run git-blame over the notes object. This is done because
+	// git-blame will become more and more expensive as the number of code reviews grows.
+	Timestamp string `json:"timestamp,omitempty"`
+	Author    string `json:"author,omitempty"`
+	// If original is provided, then the comment is an updated version of another comment.
+	Original string `json:"original,omitempty"`
+	// If parent is provided, then the comment is a response to another comment.
+	Parent string `json:"parent,omitempty"`
+	// If location is provided, then the comment is specific to that given location.
+	Location    *Location `json:"location,omitempty"`
+	Description string    `json:"description,omitempty"`
+	// The resolved bit indicates that no further action is needed.
+	//
+	// When the parent of the comment is another comment, this means that comment
+	// has been addressed. Otherwise, the parent is the commit, and this means that the
+	// change has been accepted. If the resolved bit is unset, then the comment is only an FYI.
+	Resolved *bool `json:"resolved,omitempty"`
+	// Version represents the version of the metadata format.
+	Version int `json:"v,omitempty"`
+
+	gpg.Sig
+}
+
+// New returns a new comment with the given description message.
+//
+// The Timestamp and Author fields are automatically filled in with the current time and user.
+func New(author string, description string) Comment {
+	return Comment{
+		Timestamp:   strconv.FormatInt(time.Now().Unix(), 10),
+		Author:      author,
+		Description: description,
+	}
+}
+
+// Parse parses a review comment from a git note.
+func Parse(note repository.Note) (Comment, error) {
+	bytes := []byte(note)
+	var comment Comment
+	err := json.Unmarshal(bytes, &comment)
+	return comment, err
+}
+
+// ParseAllValid takes collection of git notes and tries to parse a review
+// comment from each one. Any notes that are not valid review comments get
+// ignored, as we expect the git notes to be a heterogenous list, with only
+// some of them being review comments.
+func ParseAllValid(notes []repository.Note) map[string]Comment {
+	comments := make(map[string]Comment)
+	for _, note := range notes {
+		comment, err := Parse(note)
+		if err == nil && comment.Version == FormatVersion {
+			hash, err := comment.Hash()
+			if err == nil {
+				comments[hash] = comment
+			}
+		}
+	}
+	return comments
+}
+
+func (comment Comment) serialize() ([]byte, error) {
+	if len(comment.Timestamp) < 10 {
+		// To make sure that timestamps from before 2001 appear in the correct
+		// alphabetical order, we reformat the timestamp to be at least 10 characters
+		// and zero-padded.
+		time, err := strconv.ParseInt(comment.Timestamp, 10, 64)
+		if err == nil {
+			comment.Timestamp = fmt.Sprintf("%010d", time)
+		}
+		// We ignore the other case, as the comment timestamp is not in a format
+		// we expected, so we should just leave it alone.
+	}
+	return json.Marshal(comment)
+}
+
+// Write writes a review comment as a JSON-formatted git note.
+func (comment Comment) Write() (repository.Note, error) {
+	bytes, err := comment.serialize()
+	return repository.Note(bytes), err
+}
+
+// Hash returns the SHA1 hash of a review comment.
+func (comment Comment) Hash() (string, error) {
+	bytes, err := comment.serialize()
+	return fmt.Sprintf("%x", sha1.Sum(bytes)), err
+}
+
+// Set implenents flag.Value for the Range type
+func (r *Range) Set(s string) error {
+	var err error
+	*r = Range{}
+
+	if s == "" {
+		return nil
+	}
+	startEndParts := strings.Split(s, ":")
+	if len(startEndParts) > 2 {
+		return ErrInvalidRange
+	}
+
+	r.StartLine, r.StartColumn, err = parseRangePart(startEndParts[0])
+	if err != nil {
+		return err
+	}
+	if len(startEndParts) == 1 {
+		return nil
+	}
+
+	r.EndLine, r.EndColumn, err = parseRangePart(startEndParts[1])
+	if err != nil {
+		return err
+	}
+
+	if r.StartLine > r.EndLine {
+		return errors.New("start line cannot be greater than end line in range")
+	}
+
+	return nil
+}
+
+func parseRangePart(s string) (uint32, uint32, error) {
+	parts := strings.Split(s, "+")
+	if len(parts) > 2 {
+		return 0, 0, ErrInvalidRange
+	}
+
+	line, err := strconv.ParseUint(parts[0], 10, 32)
+	if err != nil {
+		return 0, 0, ErrInvalidRange
+	}
+
+	if len(parts) == 1 {
+		return uint32(line), 0, nil
+	}
+
+	col, err := strconv.ParseUint(parts[1], 10, 32)
+	if err != nil {
+		return 0, 0, ErrInvalidRange
+	}
+
+	if line == 0 && col != 0 {
+		// line 0 represents the entire file
+		return 0, 0, ErrInvalidRange
+	}
+
+	return uint32(line), uint32(col), nil
+}
+
+func (r *Range) String() string {
+	out := ""
+	if r.StartLine != 0 {
+		out = fmt.Sprintf("%d", r.StartLine)
+	}
+	if r.StartColumn != 0 {
+		out = fmt.Sprintf("%s+%d", out, r.StartColumn)
+	}
+	if r.EndLine != 0 {
+		out = fmt.Sprintf("%s:%d", out, r.EndLine)
+	}
+	if r.EndColumn != 0 {
+		out = fmt.Sprintf("%s+%d", out, r.EndColumn)
+	}
+	return out
+}