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- // Copyright 2019 The go-ethereum Authors
- // This file is part of the go-ethereum library.
- //
- // The go-ethereum library is free software: you can redistribute it and/or modify
- // it under the terms of the GNU Lesser General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // The go-ethereum library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU Lesser General Public License for more details.
- //
- // You should have received a copy of the GNU Lesser General Public License
- // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
- package build
- import (
- "bufio"
- "crypto/sha256"
- "encoding/hex"
- "fmt"
- "io"
- "io/ioutil"
- "log"
- "net/http"
- "os"
- "path/filepath"
- "strings"
- )
- // ChecksumDB keeps file checksums.
- type ChecksumDB struct {
- allChecksums []string
- }
- // MustLoadChecksums loads a file containing checksums.
- func MustLoadChecksums(file string) *ChecksumDB {
- content, err := ioutil.ReadFile(file)
- if err != nil {
- log.Fatal("can't load checksum file: " + err.Error())
- }
- return &ChecksumDB{strings.Split(string(content), "\n")}
- }
- // Verify checks whether the given file is valid according to the checksum database.
- func (db *ChecksumDB) Verify(path string) error {
- fd, err := os.Open(path)
- if err != nil {
- return err
- }
- defer fd.Close()
- h := sha256.New()
- if _, err := io.Copy(h, bufio.NewReader(fd)); err != nil {
- return err
- }
- fileHash := hex.EncodeToString(h.Sum(nil))
- if !db.findHash(filepath.Base(path), fileHash) {
- return fmt.Errorf("invalid file hash %s", fileHash)
- }
- return nil
- }
- func (db *ChecksumDB) findHash(basename, hash string) bool {
- want := hash + " " + basename
- for _, line := range db.allChecksums {
- if strings.TrimSpace(line) == want {
- return true
- }
- }
- return false
- }
- // DownloadFile downloads a file and verifies its checksum.
- func (db *ChecksumDB) DownloadFile(url, dstPath string) error {
- if err := db.Verify(dstPath); err == nil {
- fmt.Printf("%s is up-to-date\n", dstPath)
- return nil
- }
- fmt.Printf("%s is stale\n", dstPath)
- fmt.Printf("downloading from %s\n", url)
- resp, err := http.Get(url)
- if err != nil {
- return fmt.Errorf("download error: %v", err)
- } else if resp.StatusCode != http.StatusOK {
- return fmt.Errorf("download error: status %d", resp.StatusCode)
- }
- defer resp.Body.Close()
- if err := os.MkdirAll(filepath.Dir(dstPath), 0755); err != nil {
- return err
- }
- fd, err := os.OpenFile(dstPath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
- if err != nil {
- return err
- }
- dst := newDownloadWriter(fd, resp.ContentLength)
- _, err = io.Copy(dst, resp.Body)
- dst.Close()
- if err != nil {
- return err
- }
- return db.Verify(dstPath)
- }
- type downloadWriter struct {
- file *os.File
- dstBuf *bufio.Writer
- size int64
- written int64
- lastpct int64
- }
- func newDownloadWriter(dst *os.File, size int64) *downloadWriter {
- return &downloadWriter{
- file: dst,
- dstBuf: bufio.NewWriter(dst),
- size: size,
- }
- }
- func (w *downloadWriter) Write(buf []byte) (int, error) {
- n, err := w.dstBuf.Write(buf)
- // Report progress.
- w.written += int64(n)
- pct := w.written * 10 / w.size * 10
- if pct != w.lastpct {
- if w.lastpct != 0 {
- fmt.Print("...")
- }
- fmt.Print(pct, "%")
- w.lastpct = pct
- }
- return n, err
- }
- func (w *downloadWriter) Close() error {
- if w.lastpct > 0 {
- fmt.Println() // Finish the progress line.
- }
- flushErr := w.dstBuf.Flush()
- closeErr := w.file.Close()
- if flushErr != nil {
- return flushErr
- }
- return closeErr
- }
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