Scott Baker | 4a35a70 | 2019-11-26 08:17:33 -0800 | [diff] [blame] | 1 | package protoparse |
| 2 | |
| 3 | import ( |
| 4 | "errors" |
| 5 | "fmt" |
| 6 | "os" |
| 7 | "path/filepath" |
| 8 | "strings" |
| 9 | ) |
| 10 | |
| 11 | var errNoImportPathsForAbsoluteFilePath = errors.New("must specify at least one import path if any absolute file paths are given") |
| 12 | |
| 13 | // ResolveFilenames tries to resolve fileNames into paths that are relative to |
| 14 | // directories in the given importPaths. The returned slice has the results in |
| 15 | // the same order as they are supplied in fileNames. |
| 16 | // |
| 17 | // The resulting names should be suitable for passing to Parser.ParseFiles. |
| 18 | // |
| 19 | // If no import paths are given and any file name is absolute, this returns an |
| 20 | // error. If no import paths are given and all file names are relative, this |
| 21 | // returns the original file names. If a file name is already relative to one |
| 22 | // of the given import paths, it will be unchanged in the returned slice. If a |
| 23 | // file name given is relative to the current working directory, it will be made |
| 24 | // relative to one of the given import paths; but if it cannot be made relative |
| 25 | // (due to no matching import path), an error will be returned. |
| 26 | func ResolveFilenames(importPaths []string, fileNames ...string) ([]string, error) { |
| 27 | if len(importPaths) == 0 { |
| 28 | if containsAbsFilePath(fileNames) { |
| 29 | // We have to do this as otherwise parseProtoFiles can result in duplicate symbols. |
| 30 | // For example, assume we import "foo/bar/bar.proto" in a file "/home/alice/dev/foo/bar/baz.proto" |
| 31 | // as we call ParseFiles("/home/alice/dev/foo/bar/bar.proto","/home/alice/dev/foo/bar/baz.proto") |
| 32 | // with "/home/alice/dev" as our current directory. Due to the recursive nature of parseProtoFiles, |
| 33 | // it will discover the import "foo/bar/bar.proto" in the input file, and call parse on this, |
| 34 | // adding "foo/bar/bar.proto" to the parsed results, as well as "/home/alice/dev/foo/bar/bar.proto" |
| 35 | // from the input file list. This will result in a |
| 36 | // 'duplicate symbol SYMBOL: already defined as field in "/home/alice/dev/foo/bar/bar.proto' |
| 37 | // error being returned from ParseFiles. |
| 38 | return nil, errNoImportPathsForAbsoluteFilePath |
| 39 | } |
| 40 | return fileNames, nil |
| 41 | } |
| 42 | absImportPaths, err := absoluteFilePaths(importPaths) |
| 43 | if err != nil { |
| 44 | return nil, err |
| 45 | } |
| 46 | resolvedFileNames := make([]string, 0, len(fileNames)) |
| 47 | for _, fileName := range fileNames { |
| 48 | resolvedFileName, err := resolveFilename(absImportPaths, fileName) |
| 49 | if err != nil { |
| 50 | return nil, err |
| 51 | } |
| 52 | resolvedFileNames = append(resolvedFileNames, resolvedFileName) |
| 53 | } |
| 54 | return resolvedFileNames, nil |
| 55 | } |
| 56 | |
| 57 | func containsAbsFilePath(filePaths []string) bool { |
| 58 | for _, filePath := range filePaths { |
| 59 | if filepath.IsAbs(filePath) { |
| 60 | return true |
| 61 | } |
| 62 | } |
| 63 | return false |
| 64 | } |
| 65 | |
| 66 | func absoluteFilePaths(filePaths []string) ([]string, error) { |
| 67 | absFilePaths := make([]string, 0, len(filePaths)) |
| 68 | for _, filePath := range filePaths { |
| 69 | absFilePath, err := canonicalize(filePath) |
| 70 | if err != nil { |
| 71 | return nil, err |
| 72 | } |
| 73 | absFilePaths = append(absFilePaths, absFilePath) |
| 74 | } |
| 75 | return absFilePaths, nil |
| 76 | } |
| 77 | |
| 78 | func canonicalize(filePath string) (string, error) { |
| 79 | absPath, err := filepath.Abs(filePath) |
| 80 | if err != nil { |
| 81 | return "", err |
| 82 | } |
| 83 | // this is kind of gross, but it lets us construct a resolved path even if some |
| 84 | // path elements do not exist (a single call to filepath.EvalSymlinks would just |
| 85 | // return an error, ENOENT, in that case). |
| 86 | head := absPath |
| 87 | tail := "" |
| 88 | for { |
| 89 | noLinks, err := filepath.EvalSymlinks(head) |
| 90 | if err == nil { |
| 91 | if tail != "" { |
| 92 | return filepath.Join(noLinks, tail), nil |
| 93 | } |
| 94 | return noLinks, nil |
| 95 | } |
| 96 | |
| 97 | if tail == "" { |
| 98 | tail = filepath.Base(head) |
| 99 | } else { |
| 100 | tail = filepath.Join(filepath.Base(head), tail) |
| 101 | } |
| 102 | head = filepath.Dir(head) |
| 103 | if head == "." { |
| 104 | // ran out of path elements to try to resolve |
| 105 | return absPath, nil |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | const dotPrefix = "." + string(filepath.Separator) |
| 111 | const dotDotPrefix = ".." + string(filepath.Separator) |
| 112 | |
| 113 | func resolveFilename(absImportPaths []string, fileName string) (string, error) { |
| 114 | if filepath.IsAbs(fileName) { |
| 115 | return resolveAbsFilename(absImportPaths, fileName) |
| 116 | } |
| 117 | |
| 118 | if !strings.HasPrefix(fileName, dotPrefix) && !strings.HasPrefix(fileName, dotDotPrefix) { |
| 119 | // Use of . and .. are assumed to be relative to current working |
| 120 | // directory. So if those aren't present, check to see if the file is |
| 121 | // relative to an import path. |
| 122 | for _, absImportPath := range absImportPaths { |
| 123 | absFileName := filepath.Join(absImportPath, fileName) |
| 124 | _, err := os.Stat(absFileName) |
| 125 | if err != nil { |
| 126 | continue |
| 127 | } |
| 128 | // found it! it was relative to this import path |
| 129 | return fileName, nil |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | // must be relative to current working dir |
| 134 | return resolveAbsFilename(absImportPaths, fileName) |
| 135 | } |
| 136 | |
| 137 | func resolveAbsFilename(absImportPaths []string, fileName string) (string, error) { |
| 138 | absFileName, err := canonicalize(fileName) |
| 139 | if err != nil { |
| 140 | return "", err |
| 141 | } |
| 142 | for _, absImportPath := range absImportPaths { |
| 143 | if isDescendant(absImportPath, absFileName) { |
| 144 | resolvedPath, err := filepath.Rel(absImportPath, absFileName) |
| 145 | if err != nil { |
| 146 | return "", err |
| 147 | } |
| 148 | return resolvedPath, nil |
| 149 | } |
| 150 | } |
| 151 | return "", fmt.Errorf("%s does not reside in any import path", fileName) |
| 152 | } |
| 153 | |
| 154 | // isDescendant returns true if file is a descendant of dir. Both dir and file must |
| 155 | // be cleaned, absolute paths. |
| 156 | func isDescendant(dir, file string) bool { |
| 157 | dir = filepath.Clean(dir) |
| 158 | cur := file |
| 159 | for { |
| 160 | d := filepath.Dir(cur) |
| 161 | if d == dir { |
| 162 | return true |
| 163 | } |
| 164 | if d == "." || d == cur { |
| 165 | // we've run out of path elements |
| 166 | return false |
| 167 | } |
| 168 | cur = d |
| 169 | } |
| 170 | } |