manifest.go

Documentation: github.com/bazelbuild/rules_go/go/runfiles

     1  // Copyright 2020, 2021 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     https://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package runfiles
    16  
    17  import (
    18  	"bufio"
    19  	"fmt"
    20  	"os"
    21  	"path"
    22  	"path/filepath"
    23  	"strings"
    24  )
    25  
    26  // ManifestFile specifies the location of the runfile manifest file.  You can
    27  // pass this as an option to New.  If unset or empty, use the value of the
    28  // environmental variable RUNFILES_MANIFEST_FILE.
    29  type ManifestFile string
    30  
    31  func (f ManifestFile) new(sourceRepo SourceRepo) (*Runfiles, error) {
    32  	m, err := f.parse()
    33  	if err != nil {
    34  		return nil, err
    35  	}
    36  	env := []string{
    37  		manifestFileVar + "=" + string(f),
    38  	}
    39  	// Certain tools (e.g., Java tools) may need the runfiles directory, so try to find it even if
    40  	// running with a manifest file.
    41  	if strings.HasSuffix(string(f), ".runfiles_manifest") ||
    42  		strings.HasSuffix(string(f), "/MANIFEST") ||
    43  		strings.HasSuffix(string(f), "\\MANIFEST") {
    44  		// Cut off either "_manifest" or "/MANIFEST" or "\\MANIFEST", all of length 9, from the end
    45  		// of the path to obtain the runfiles directory.
    46  		d := string(f)[:len(string(f))-len("_manifest")]
    47  		env = append(env,
    48  			directoryVar+"="+d,
    49  			legacyDirectoryVar+"="+d)
    50  	}
    51  	r := &Runfiles{
    52  		impl:       m,
    53  		env:        env,
    54  		sourceRepo: string(sourceRepo),
    55  	}
    56  	err = r.loadRepoMapping()
    57  	return r, err
    58  }
    59  
    60  type manifest map[string]string
    61  
    62  func (f ManifestFile) parse() (manifest, error) {
    63  	r, err := os.Open(string(f))
    64  	if err != nil {
    65  		return nil, fmt.Errorf("runfiles: can’t open manifest file: %w", err)
    66  	}
    67  	defer r.Close()
    68  
    69  	s := bufio.NewScanner(r)
    70  	m := make(manifest)
    71  	for s.Scan() {
    72  		fields := strings.SplitN(s.Text(), " ", 2)
    73  		if len(fields) != 2 || fields[0] == "" {
    74  			return nil, fmt.Errorf("runfiles: bad manifest line %q in file %s", s.Text(), f)
    75  		}
    76  		m[fields[0]] = filepath.FromSlash(fields[1])
    77  	}
    78  
    79  	if err := s.Err(); err != nil {
    80  		return nil, fmt.Errorf("runfiles: error parsing manifest file %s: %w", f, err)
    81  	}
    82  
    83  	return m, nil
    84  }
    85  
    86  func (m manifest) path(s string) (string, error) {
    87  	r, ok := m[s]
    88  	if ok && r == "" {
    89  		return "", ErrEmpty
    90  	}
    91  	if ok {
    92  		return r, nil
    93  	}
    94  
    95  	// If path references a runfile that lies under a directory that itself is a
    96  	// runfile, then only the directory is listed in the manifest. Look up all
    97  	// prefixes of path in the manifest.
    98  	for prefix := s; prefix != ""; prefix, _ = path.Split(prefix) {
    99  		prefix = strings.TrimSuffix(prefix, "/")
   100  		if prefixMatch, ok := m[prefix]; ok {
   101  			return prefixMatch + filepath.FromSlash(strings.TrimPrefix(s, prefix)), nil
   102  		}
   103  	}
   104  
   105  	return "", os.ErrNotExist
   106  }
   107
View as plain text