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 "regexp" 19 "runtime" 20 "sync" 21 ) 22 23 // Rlocation returns the absolute path name of a runfile. The runfile name must be 24 // a relative path, using the slash (not backslash) as directory separator. If 25 // the runfiles manifest maps s to an empty name (indicating an empty runfile 26 // not present in the filesystem), Rlocation returns an error that wraps ErrEmpty. 27 func Rlocation(path string) (string, error) { 28 return RlocationFrom(path, CallerRepository()) 29 } 30 31 func RlocationFrom(path string, sourceRepo string) (string, error) { 32 r, err := g.get() 33 if err != nil { 34 return "", err 35 } 36 return r.WithSourceRepo(sourceRepo).Rlocation(path) 37 } 38 39 // Env returns additional environmental variables to pass to subprocesses. 40 // Each element is of the form “key=value”. Pass these variables to 41 // Bazel-built binaries so they can find their runfiles as well. See the 42 // Runfiles example for an illustration of this. 43 // 44 // The return value is a newly-allocated slice; you can modify it at will. 45 func Env() ([]string, error) { 46 r, err := g.get() 47 if err != nil { 48 return nil, err 49 } 50 return r.Env(), nil 51 } 52 53 var legacyExternalGeneratedFile = regexp.MustCompile(`^bazel-out[/][^/]+/bin/external/([^/]+)/`) 54 var legacyExternalFile = regexp.MustCompile(`^external/([^/]+)/`) 55 56 // CurrentRepository returns the canonical name of the Bazel repository that 57 // contains the source file of the caller of CurrentRepository. 58 func CurrentRepository() string { 59 return callerRepository(1) 60 } 61 62 // CallerRepository returns the canonical name of the Bazel repository that 63 // contains the source file of the caller of the function that itself calls 64 // CallerRepository. 65 func CallerRepository() string { 66 return callerRepository(2) 67 } 68 69 func callerRepository(skip int) string { 70 _, file, _, _ := runtime.Caller(skip + 1) 71 if match := legacyExternalGeneratedFile.FindStringSubmatch(file); match != nil { 72 return match[1] 73 } 74 if match := legacyExternalFile.FindStringSubmatch(file); match != nil { 75 return match[1] 76 } 77 // If a file is not in an external repository, it is in the main repository, 78 // which has the empty string as its canonical name. 79 return "" 80 } 81 82 type global struct { 83 once sync.Once 84 runfiles *Runfiles 85 err error 86 } 87 88 func (g *global) get() (*Runfiles, error) { 89 g.once.Do(g.init) 90 return g.runfiles, g.err 91 } 92 93 func (g *global) init() { 94 g.runfiles, g.err = New() 95 } 96 97 var g global 98