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forgejo/routers/web/repo/blame.go
Lunny Xiao bd820aa9c5
Add context cache as a request level cache (#22294)
To avoid duplicated load of the same data in an HTTP request, we can set
a context cache to do that. i.e. Some pages may load a user from a
database with the same id in different areas on the same page. But the
code is hidden in two different deep logic. How should we share the
user? As a result of this PR, now if both entry functions accept
`context.Context` as the first parameter and we just need to refactor
`GetUserByID` to reuse the user from the context cache. Then it will not
be loaded twice on an HTTP request.

But of course, sometimes we would like to reload an object from the
database, that's why `RemoveContextData` is also exposed.

The core context cache is here. It defines a new context
```go
type cacheContext struct {
	ctx  context.Context
	data map[any]map[any]any
        lock sync.RWMutex
}

var cacheContextKey = struct{}{}

func WithCacheContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, cacheContextKey, &cacheContext{
		ctx:  ctx,
		data: make(map[any]map[any]any),
	})
}
```

Then you can use the below 4 methods to read/write/del the data within
the same context.

```go
func GetContextData(ctx context.Context, tp, key any) any
func SetContextData(ctx context.Context, tp, key, value any)
func RemoveContextData(ctx context.Context, tp, key any)
func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error)
```

Then let's take a look at how `system.GetString` implement it.

```go
func GetSetting(ctx context.Context, key string) (string, error) {
	return cache.GetWithContextCache(ctx, contextCacheKey, key, func() (string, error) {
		return cache.GetString(genSettingCacheKey(key), func() (string, error) {
			res, err := GetSettingNoCache(ctx, key)
			if err != nil {
				return "", err
			}
			return res.SettingValue, nil
		})
	})
}
```

First, it will check if context data include the setting object with the
key. If not, it will query from the global cache which may be memory or
a Redis cache. If not, it will get the object from the database. In the
end, if the object gets from the global cache or database, it will be
set into the context cache.

An object stored in the context cache will only be destroyed after the
context disappeared.
2023-02-15 21:37:34 +08:00

304 lines
8.2 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package repo
import (
"fmt"
gotemplate "html/template"
"net/http"
"net/url"
"strings"
repo_model "code.gitea.io/gitea/models/repo"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/charset"
"code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/highlight"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/templates"
"code.gitea.io/gitea/modules/timeutil"
"code.gitea.io/gitea/modules/util"
)
const (
tplBlame base.TplName = "repo/home"
)
type blameRow struct {
RowNumber int
Avatar gotemplate.HTML
RepoLink string
PartSha string
PreviousSha string
PreviousShaURL string
IsFirstCommit bool
CommitURL string
CommitMessage string
CommitSince gotemplate.HTML
Code gotemplate.HTML
EscapeStatus *charset.EscapeStatus
}
// RefBlame render blame page
func RefBlame(ctx *context.Context) {
fileName := ctx.Repo.TreePath
if len(fileName) == 0 {
ctx.NotFound("Blame FileName", nil)
return
}
userName := ctx.Repo.Owner.Name
repoName := ctx.Repo.Repository.Name
commitID := ctx.Repo.CommitID
branchLink := ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
treeLink := branchLink
rawLink := ctx.Repo.RepoLink + "/raw/" + ctx.Repo.BranchNameSubURL()
if len(ctx.Repo.TreePath) > 0 {
treeLink += "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
}
var treeNames []string
paths := make([]string, 0, 5)
if len(ctx.Repo.TreePath) > 0 {
treeNames = strings.Split(ctx.Repo.TreePath, "/")
for i := range treeNames {
paths = append(paths, strings.Join(treeNames[:i+1], "/"))
}
ctx.Data["HasParentPath"] = true
if len(paths)-2 >= 0 {
ctx.Data["ParentPath"] = "/" + paths[len(paths)-1]
}
}
// Get current entry user currently looking at.
entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
if err != nil {
ctx.NotFoundOrServerError("Repo.Commit.GetTreeEntryByPath", git.IsErrNotExist, err)
return
}
blob := entry.Blob()
ctx.Data["Paths"] = paths
ctx.Data["TreeLink"] = treeLink
ctx.Data["TreeNames"] = treeNames
ctx.Data["BranchLink"] = branchLink
ctx.Data["RawFileLink"] = rawLink + "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
ctx.Data["PageIsViewCode"] = true
ctx.Data["IsBlame"] = true
ctx.Data["FileSize"] = blob.Size()
ctx.Data["FileName"] = blob.Name()
ctx.Data["NumLines"], err = blob.GetBlobLineCount()
ctx.Data["NumLinesSet"] = true
if err != nil {
ctx.NotFound("GetBlobLineCount", err)
return
}
blameReader, err := git.CreateBlameReader(ctx, repo_model.RepoPath(userName, repoName), commitID, fileName)
if err != nil {
ctx.NotFound("CreateBlameReader", err)
return
}
defer blameReader.Close()
blameParts := make([]git.BlamePart, 0)
for {
blamePart, err := blameReader.NextPart()
if err != nil {
ctx.NotFound("NextPart", err)
return
}
if blamePart == nil {
break
}
blameParts = append(blameParts, *blamePart)
}
// Get Topics of this repo
renderRepoTopics(ctx)
if ctx.Written() {
return
}
commitNames, previousCommits := processBlameParts(ctx, blameParts)
if ctx.Written() {
return
}
renderBlame(ctx, blameParts, commitNames, previousCommits)
ctx.HTML(http.StatusOK, tplBlame)
}
func processBlameParts(ctx *context.Context, blameParts []git.BlamePart) (map[string]*user_model.UserCommit, map[string]string) {
// store commit data by SHA to look up avatar info etc
commitNames := make(map[string]*user_model.UserCommit)
// previousCommits contains links from SHA to parent SHA,
// if parent also contains the current TreePath.
previousCommits := make(map[string]string)
// and as blameParts can reference the same commits multiple
// times, we cache the lookup work locally
commits := make([]*git.Commit, 0, len(blameParts))
commitCache := map[string]*git.Commit{}
commitCache[ctx.Repo.Commit.ID.String()] = ctx.Repo.Commit
for _, part := range blameParts {
sha := part.Sha
if _, ok := commitNames[sha]; ok {
continue
}
// find the blamePart commit, to look up parent & email address for avatars
commit, ok := commitCache[sha]
var err error
if !ok {
commit, err = ctx.Repo.GitRepo.GetCommit(sha)
if err != nil {
if git.IsErrNotExist(err) {
ctx.NotFound("Repo.GitRepo.GetCommit", err)
} else {
ctx.ServerError("Repo.GitRepo.GetCommit", err)
}
return nil, nil
}
commitCache[sha] = commit
}
// find parent commit
if commit.ParentCount() > 0 {
psha := commit.Parents[0]
previousCommit, ok := commitCache[psha.String()]
if !ok {
previousCommit, _ = commit.Parent(0)
if previousCommit != nil {
commitCache[psha.String()] = previousCommit
}
}
// only store parent commit ONCE, if it has the file
if previousCommit != nil {
if haz1, _ := previousCommit.HasFile(ctx.Repo.TreePath); haz1 {
previousCommits[commit.ID.String()] = previousCommit.ID.String()
}
}
}
commits = append(commits, commit)
}
// populate commit email addresses to later look up avatars.
for _, c := range user_model.ValidateCommitsWithEmails(ctx, commits) {
commitNames[c.ID.String()] = c
}
return commitNames, previousCommits
}
func renderBlame(ctx *context.Context, blameParts []git.BlamePart, commitNames map[string]*user_model.UserCommit, previousCommits map[string]string) {
repoLink := ctx.Repo.RepoLink
language := ""
indexFilename, worktree, deleteTemporaryFile, err := ctx.Repo.GitRepo.ReadTreeToTemporaryIndex(ctx.Repo.CommitID)
if err == nil {
defer deleteTemporaryFile()
filename2attribute2info, err := ctx.Repo.GitRepo.CheckAttribute(git.CheckAttributeOpts{
CachedOnly: true,
Attributes: []string{"linguist-language", "gitlab-language"},
Filenames: []string{ctx.Repo.TreePath},
IndexFile: indexFilename,
WorkTree: worktree,
})
if err != nil {
log.Error("Unable to load attributes for %-v:%s. Error: %v", ctx.Repo.Repository, ctx.Repo.TreePath, err)
}
language = filename2attribute2info[ctx.Repo.TreePath]["linguist-language"]
if language == "" || language == "unspecified" {
language = filename2attribute2info[ctx.Repo.TreePath]["gitlab-language"]
}
if language == "unspecified" {
language = ""
}
}
lines := make([]string, 0)
rows := make([]*blameRow, 0)
escapeStatus := &charset.EscapeStatus{}
var lexerName string
i := 0
commitCnt := 0
for _, part := range blameParts {
for index, line := range part.Lines {
i++
lines = append(lines, line)
br := &blameRow{
RowNumber: i,
}
commit := commitNames[part.Sha]
previousSha := previousCommits[part.Sha]
if index == 0 {
// Count commit number
commitCnt++
// User avatar image
commitSince := timeutil.TimeSinceUnix(timeutil.TimeStamp(commit.Author.When.Unix()), ctx.Locale)
var avatar string
if commit.User != nil {
avatar = string(templates.Avatar(ctx, commit.User, 18, "gt-mr-3"))
} else {
avatar = string(templates.AvatarByEmail(ctx, commit.Author.Email, commit.Author.Name, 18, "gt-mr-3"))
}
br.Avatar = gotemplate.HTML(avatar)
br.RepoLink = repoLink
br.PartSha = part.Sha
br.PreviousSha = previousSha
br.PreviousShaURL = fmt.Sprintf("%s/blame/commit/%s/%s", repoLink, url.PathEscape(previousSha), util.PathEscapeSegments(ctx.Repo.TreePath))
br.CommitURL = fmt.Sprintf("%s/commit/%s", repoLink, url.PathEscape(part.Sha))
br.CommitMessage = commit.CommitMessage
br.CommitSince = commitSince
}
if i != len(lines)-1 {
line += "\n"
}
fileName := fmt.Sprintf("%v", ctx.Data["FileName"])
line, lexerNameForLine := highlight.Code(fileName, language, line)
// set lexer name to the first detected lexer. this is certainly suboptimal and
// we should instead highlight the whole file at once
if lexerName == "" {
lexerName = lexerNameForLine
}
br.EscapeStatus, line = charset.EscapeControlHTML(line, ctx.Locale)
br.Code = gotemplate.HTML(line)
rows = append(rows, br)
escapeStatus = escapeStatus.Or(br.EscapeStatus)
}
}
ctx.Data["EscapeStatus"] = escapeStatus
ctx.Data["BlameRows"] = rows
ctx.Data["CommitCnt"] = commitCnt
ctx.Data["LexerName"] = lexerName
}