syncthing/cmd/stcrashreceiver/sourcecodeloader.go
2020-08-18 12:54:20 +02:00

119 lines
2.5 KiB
Go

// Copyright (C) 2019 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package main
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
"path/filepath"
"strings"
"sync"
"time"
)
const (
urlPrefix = "https://raw.githubusercontent.com/syncthing/syncthing/"
httpTimeout = 10 * time.Second
)
type githubSourceCodeLoader struct {
mut sync.Mutex
version string
cache map[string]map[string][][]byte // version -> file -> lines
client *http.Client
}
func newGithubSourceCodeLoader() *githubSourceCodeLoader {
return &githubSourceCodeLoader{
cache: make(map[string]map[string][][]byte),
client: &http.Client{Timeout: httpTimeout},
}
}
func (l *githubSourceCodeLoader) LockWithVersion(version string) {
l.mut.Lock()
l.version = version
if _, ok := l.cache[version]; !ok {
l.cache[version] = make(map[string][][]byte)
}
}
func (l *githubSourceCodeLoader) Unlock() {
l.mut.Unlock()
}
func (l *githubSourceCodeLoader) Load(filename string, line, context int) ([][]byte, int) {
filename = filepath.ToSlash(filename)
lines, ok := l.cache[l.version][filename]
if !ok {
// Cache whatever we managed to find (or nil if nothing, so we don't try again)
defer func() {
l.cache[l.version][filename] = lines
}()
knownPrefixes := []string{"/lib/", "/cmd/"}
var idx int
for _, pref := range knownPrefixes {
idx = strings.Index(filename, pref)
if idx >= 0 {
break
}
}
if idx == -1 {
return nil, 0
}
url := urlPrefix + l.version + filename[idx:]
resp, err := l.client.Get(url)
if err != nil {
fmt.Println("Loading source:", err)
return nil, 0
}
if resp.StatusCode != http.StatusOK {
fmt.Println("Loading source:", resp.Status)
return nil, 0
}
data, err := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
if err != nil {
fmt.Println("Loading source:", err.Error())
return nil, 0
}
lines = bytes.Split(data, []byte{'\n'})
}
return getLineFromLines(lines, line, context)
}
func getLineFromLines(lines [][]byte, line, context int) ([][]byte, int) {
if lines == nil {
// cached error from ReadFile: return no lines
return nil, 0
}
line-- // stack trace lines are 1-indexed
start := line - context
var idx int
if start < 0 {
start = 0
idx = line
} else {
idx = context
}
end := line + context + 1
if line >= len(lines) {
return nil, 0
}
if end > len(lines) {
end = len(lines)
}
return lines[start:end], idx
}