svn.go

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package codehost
     6  
     7  import (
     8  	"archive/zip"
     9  	"encoding/xml"
    10  	"fmt"
    11  	"io"
    12  	"os"
    13  	"path"
    14  	"path/filepath"
    15  	"time"
    16  )
    17  
    18  func svnParseStat(rev, out string) (*RevInfo, error) {
    19  	var log struct {
    20  		Logentry struct {
    21  			Revision int64  `xml:"revision,attr"`
    22  			Date     string `xml:"date"`
    23  		} `xml:"logentry"`
    24  	}
    25  	if err := xml.Unmarshal([]byte(out), &log); err != nil {
    26  		return nil, vcsErrorf("unexpected response from svn log --xml: %v\n%s", err, out)
    27  	}
    28  
    29  	t, err := time.Parse(time.RFC3339, log.Logentry.Date)
    30  	if err != nil {
    31  		return nil, vcsErrorf("unexpected response from svn log --xml: %v\n%s", err, out)
    32  	}
    33  
    34  	info := &RevInfo{
    35  		Name:    fmt.Sprintf("%d", log.Logentry.Revision),
    36  		Short:   fmt.Sprintf("%012d", log.Logentry.Revision),
    37  		Time:    t.UTC(),
    38  		Version: rev,
    39  	}
    40  	return info, nil
    41  }
    42  
    43  func svnReadZip(dst io.Writer, workDir, rev, subdir, remote string) (err error) {
    44  	// The subversion CLI doesn't provide a command to write the repository
    45  	// directly to an archive, so we need to export it to the local filesystem
    46  	// instead. Unfortunately, the local filesystem might apply arbitrary
    47  	// normalization to the filenames, so we need to obtain those directly.
    48  	//
    49  	// 'svn export' prints the filenames as they are written, but from reading the
    50  	// svn source code (as of revision 1868933), those filenames are encoded using
    51  	// the system locale rather than preserved byte-for-byte from the origin. For
    52  	// our purposes, that won't do, but we don't want to go mucking around with
    53  	// the user's locale settings either — that could impact error messages, and
    54  	// we don't know what locales the user has available or what LC_* variables
    55  	// their platform supports.
    56  	//
    57  	// Instead, we'll do a two-pass export: first we'll run 'svn list' to get the
    58  	// canonical filenames, then we'll 'svn export' and look for those filenames
    59  	// in the local filesystem. (If there is an encoding problem at that point, we
    60  	// would probably reject the resulting module anyway.)
    61  
    62  	remotePath := remote
    63  	if subdir != "" {
    64  		remotePath += "/" + subdir
    65  	}
    66  
    67  	out, err := Run(workDir, []string{
    68  		"svn", "list",
    69  		"--non-interactive",
    70  		"--xml",
    71  		"--incremental",
    72  		"--recursive",
    73  		"--revision", rev,
    74  		"--", remotePath,
    75  	})
    76  	if err != nil {
    77  		return err
    78  	}
    79  
    80  	type listEntry struct {
    81  		Kind string `xml:"kind,attr"`
    82  		Name string `xml:"name"`
    83  		Size int64  `xml:"size"`
    84  	}
    85  	var list struct {
    86  		Entries []listEntry `xml:"entry"`
    87  	}
    88  	if err := xml.Unmarshal(out, &list); err != nil {
    89  		return vcsErrorf("unexpected response from svn list --xml: %v\n%s", err, out)
    90  	}
    91  
    92  	exportDir := filepath.Join(workDir, "export")
    93  	// Remove any existing contents from a previous (failed) run.
    94  	if err := os.RemoveAll(exportDir); err != nil {
    95  		return err
    96  	}
    97  	defer os.RemoveAll(exportDir) // best-effort
    98  
    99  	_, err = Run(workDir, []string{
   100  		"svn", "export",
   101  		"--non-interactive",
   102  		"--quiet",
   103  
   104  		// Suppress any platform- or host-dependent transformations.
   105  		"--native-eol", "LF",
   106  		"--ignore-externals",
   107  		"--ignore-keywords",
   108  
   109  		"--revision", rev,
   110  		"--", remotePath,
   111  		exportDir,
   112  	})
   113  	if err != nil {
   114  		return err
   115  	}
   116  
   117  	// Scrape the exported files out of the filesystem and encode them in the zipfile.
   118  
   119  	// “All files in the zip file are expected to be
   120  	// nested in a single top-level directory, whose name is not specified.”
   121  	// We'll (arbitrarily) choose the base of the remote path.
   122  	basePath := path.Join(path.Base(remote), subdir)
   123  
   124  	zw := zip.NewWriter(dst)
   125  	for _, e := range list.Entries {
   126  		if e.Kind != "file" {
   127  			continue
   128  		}
   129  
   130  		zf, err := zw.Create(path.Join(basePath, e.Name))
   131  		if err != nil {
   132  			return err
   133  		}
   134  
   135  		f, err := os.Open(filepath.Join(exportDir, e.Name))
   136  		if err != nil {
   137  			if os.IsNotExist(err) {
   138  				return vcsErrorf("file reported by 'svn list', but not written by 'svn export': %s", e.Name)
   139  			}
   140  			return fmt.Errorf("error opening file created by 'svn export': %v", err)
   141  		}
   142  
   143  		n, err := io.Copy(zf, f)
   144  		f.Close()
   145  		if err != nil {
   146  			return err
   147  		}
   148  		if n != e.Size {
   149  			return vcsErrorf("file size differs between 'svn list' and 'svn export': file %s listed as %v bytes, but exported as %v bytes", e.Name, e.Size, n)
   150  		}
   151  	}
   152  
   153  	return zw.Close()
   154  }
   155
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