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Diffstat (limited to 'vendor/golang.org/x/mod/module/module.go')
| -rw-r--r-- | vendor/golang.org/x/mod/module/module.go | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/vendor/golang.org/x/mod/module/module.go b/vendor/golang.org/x/mod/module/module.go new file mode 100644 index 000000000..355b5a456 --- /dev/null +++ b/vendor/golang.org/x/mod/module/module.go @@ -0,0 +1,841 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package module defines the module.Version type along with support code. +// +// The module.Version type is a simple Path, Version pair: +// +// type Version struct { +// Path string +// Version string +// } +// +// There are no restrictions imposed directly by use of this structure, +// but additional checking functions, most notably Check, verify that +// a particular path, version pair is valid. +// +// Escaped Paths +// +// Module paths appear as substrings of file system paths +// (in the download cache) and of web server URLs in the proxy protocol. +// In general we cannot rely on file systems to be case-sensitive, +// nor can we rely on web servers, since they read from file systems. +// That is, we cannot rely on the file system to keep rsc.io/QUOTE +// and rsc.io/quote separate. Windows and macOS don't. +// Instead, we must never require two different casings of a file path. +// Because we want the download cache to match the proxy protocol, +// and because we want the proxy protocol to be possible to serve +// from a tree of static files (which might be stored on a case-insensitive +// file system), the proxy protocol must never require two different casings +// of a URL path either. +// +// One possibility would be to make the escaped form be the lowercase +// hexadecimal encoding of the actual path bytes. This would avoid ever +// needing different casings of a file path, but it would be fairly illegible +// to most programmers when those paths appeared in the file system +// (including in file paths in compiler errors and stack traces) +// in web server logs, and so on. Instead, we want a safe escaped form that +// leaves most paths unaltered. +// +// The safe escaped form is to replace every uppercase letter +// with an exclamation mark followed by the letter's lowercase equivalent. +// +// For example, +// +// github.com/Azure/azure-sdk-for-go -> github.com/!azure/azure-sdk-for-go. +// github.com/GoogleCloudPlatform/cloudsql-proxy -> github.com/!google!cloud!platform/cloudsql-proxy +// github.com/Sirupsen/logrus -> github.com/!sirupsen/logrus. +// +// Import paths that avoid upper-case letters are left unchanged. +// Note that because import paths are ASCII-only and avoid various +// problematic punctuation (like : < and >), the escaped form is also ASCII-only +// and avoids the same problematic punctuation. +// +// Import paths have never allowed exclamation marks, so there is no +// need to define how to escape a literal !. +// +// Unicode Restrictions +// +// Today, paths are disallowed from using Unicode. +// +// Although paths are currently disallowed from using Unicode, +// we would like at some point to allow Unicode letters as well, to assume that +// file systems and URLs are Unicode-safe (storing UTF-8), and apply +// the !-for-uppercase convention for escaping them in the file system. +// But there are at least two subtle considerations. +// +// First, note that not all case-fold equivalent distinct runes +// form an upper/lower pair. +// For example, U+004B ('K'), U+006B ('k'), and U+212A ('K' for Kelvin) +// are three distinct runes that case-fold to each other. +// When we do add Unicode letters, we must not assume that upper/lower +// are the only case-equivalent pairs. +// Perhaps the Kelvin symbol would be disallowed entirely, for example. +// Or perhaps it would escape as "!!k", or perhaps as "(212A)". +// +// Second, it would be nice to allow Unicode marks as well as letters, +// but marks include combining marks, and then we must deal not +// only with case folding but also normalization: both U+00E9 ('é') +// and U+0065 U+0301 ('e' followed by combining acute accent) +// look the same on the page and are treated by some file systems +// as the same path. If we do allow Unicode marks in paths, there +// must be some kind of normalization to allow only one canonical +// encoding of any character used in an import path. +package module + +// IMPORTANT NOTE +// +// This file essentially defines the set of valid import paths for the go command. +// There are many subtle considerations, including Unicode ambiguity, +// security, network, and file system representations. +// +// This file also defines the set of valid module path and version combinations, +// another topic with many subtle considerations. +// +// Changes to the semantics in this file require approval from rsc. + +import ( + "fmt" + "path" + "sort" + "strings" + "unicode" + "unicode/utf8" + + "golang.org/x/mod/semver" + errors "golang.org/x/xerrors" +) + +// A Version (for clients, a module.Version) is defined by a module path and version pair. +// These are stored in their plain (unescaped) form. +type Version struct { + // Path is a module path, like "golang.org/x/text" or "rsc.io/quote/v2". + Path string + + // Version is usually a semantic version in canonical form. + // There are three exceptions to this general rule. + // First, the top-level target of a build has no specific version + // and uses Version = "". + // Second, during MVS calculations the version "none" is used + // to represent the decision to take no version of a given module. + // Third, filesystem paths found in "replace" directives are + // represented by a path with an empty version. + Version string `json:",omitempty"` +} + +// String returns a representation of the Version suitable for logging +// (Path@Version, or just Path if Version is empty). +func (m Version) String() string { + if m.Version == "" { + return m.Path + } + return m.Path + "@" + m.Version +} + +// A ModuleError indicates an error specific to a module. +type ModuleError struct { + Path string + Version string + Err error +} + +// VersionError returns a ModuleError derived from a Version and error, +// or err itself if it is already such an error. +func VersionError(v Version, err error) error { + var mErr *ModuleError + if errors.As(err, &mErr) && mErr.Path == v.Path && mErr.Version == v.Version { + return err + } + return &ModuleError{ + Path: v.Path, + Version: v.Version, + Err: err, + } +} + +func (e *ModuleError) Error() string { + if v, ok := e.Err.(*InvalidVersionError); ok { + return fmt.Sprintf("%s@%s: invalid %s: %v", e.Path, v.Version, v.noun(), v.Err) + } + if e.Version != "" { + return fmt.Sprintf("%s@%s: %v", e.Path, e.Version, e.Err) + } + return fmt.Sprintf("module %s: %v", e.Path, e.Err) +} + +func (e *ModuleError) Unwrap() error { return e.Err } + +// An InvalidVersionError indicates an error specific to a version, with the +// module path unknown or specified externally. +// +// A ModuleError may wrap an InvalidVersionError, but an InvalidVersionError +// must not wrap a ModuleError. +type InvalidVersionError struct { + Version string + Pseudo bool + Err error +} + +// noun returns either "version" or "pseudo-version", depending on whether +// e.Version is a pseudo-version. +func (e *InvalidVersionError) noun() string { + if e.Pseudo { + return "pseudo-version" + } + return "version" +} + +func (e *InvalidVersionError) Error() string { + return fmt.Sprintf("%s %q invalid: %s", e.noun(), e.Version, e.Err) +} + +func (e *InvalidVersionError) Unwrap() error { return e.Err } + +// An InvalidPathError indicates a module, import, or file path doesn't +// satisfy all naming constraints. See CheckPath, CheckImportPath, +// and CheckFilePath for specific restrictions. +type InvalidPathError struct { + Kind string // "module", "import", or "file" + Path string + Err error +} + +func (e *InvalidPathError) Error() string { + return fmt.Sprintf("malformed %s path %q: %v", e.Kind, e.Path, e.Err) +} + +func (e *InvalidPathError) Unwrap() error { return e.Err } + +// Check checks that a given module path, version pair is valid. +// In addition to the path being a valid module path +// and the version being a valid semantic version, +// the two must correspond. +// For example, the path "yaml/v2" only corresponds to +// semantic versions beginning with "v2.". +func Check(path, version string) error { + if err := CheckPath(path); err != nil { + return err + } + if !semver.IsValid(version) { + return &ModuleError{ + Path: path, + Err: &InvalidVersionError{Version: version, Err: errors.New("not a semantic version")}, + } + } + _, pathMajor, _ := SplitPathVersion(path) + if err := CheckPathMajor(version, pathMajor); err != nil { + return &ModuleError{Path: path, Err: err} + } + return nil +} + +// firstPathOK reports whether r can appear in the first element of a module path. +// The first element of the path must be an LDH domain name, at least for now. +// To avoid case ambiguity, the domain name must be entirely lower case. +func firstPathOK(r rune) bool { + return r == '-' || r == '.' || + '0' <= r && r <= '9' || + 'a' <= r && r <= 'z' +} + +// modPathOK reports whether r can appear in a module path element. +// Paths can be ASCII letters, ASCII digits, and limited ASCII punctuation: - . _ and ~. +// +// This matches what "go get" has historically recognized in import paths, +// and avoids confusing sequences like '%20' or '+' that would change meaning +// if used in a URL. +// +// TODO(rsc): We would like to allow Unicode letters, but that requires additional +// care in the safe encoding (see "escaped paths" above). +func modPathOK(r rune) bool { + if r < utf8.RuneSelf { + return r == '-' || r == '.' || r == '_' || r == '~' || + '0' <= r && r <= '9' || + 'A' <= r && r <= 'Z' || + 'a' <= r && r <= 'z' + } + return false +} + +// modPathOK reports whether r can appear in a package import path element. +// +// Import paths are intermediate between module paths and file paths: we allow +// disallow characters that would be confusing or ambiguous as arguments to +// 'go get' (such as '@' and ' ' ), but allow certain characters that are +// otherwise-unambiguous on the command line and historically used for some +// binary names (such as '++' as a suffix for compiler binaries and wrappers). +func importPathOK(r rune) bool { + return modPathOK(r) || r == '+' +} + +// fileNameOK reports whether r can appear in a file name. +// For now we allow all Unicode letters but otherwise limit to pathOK plus a few more punctuation characters. +// If we expand the set of allowed characters here, we have to +// work harder at detecting potential case-folding and normalization collisions. +// See note about "escaped paths" above. +func fileNameOK(r rune) bool { + if r < utf8.RuneSelf { + // Entire set of ASCII punctuation, from which we remove characters: + // ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~ + // We disallow some shell special characters: " ' * < > ? ` | + // (Note that some of those are disallowed by the Windows file system as well.) + // We also disallow path separators / : and \ (fileNameOK is only called on path element characters). + // We allow spaces (U+0020) in file names. + const allowed = "!#$%&()+,-.=@[]^_{}~ " + if '0' <= r && r <= '9' || 'A' <= r && r <= 'Z' || 'a' <= r && r <= 'z' { + return true + } + return strings.ContainsRune(allowed, r) + } + // It may be OK to add more ASCII punctuation here, but only carefully. + // For example Windows disallows < > \, and macOS disallows :, so we must not allow those. + return unicode.IsLetter(r) +} + +// CheckPath checks that a module path is valid. +// A valid module path is a valid import path, as checked by CheckImportPath, +// with three additional constraints. +// First, the leading path element (up to the first slash, if any), +// by convention a domain name, must contain only lower-case ASCII letters, +// ASCII digits, dots (U+002E), and dashes (U+002D); +// it must contain at least one dot and cannot start with a dash. +// Second, for a final path element of the form /vN, where N looks numeric +// (ASCII digits and dots) must not begin with a leading zero, must not be /v1, +// and must not contain any dots. For paths beginning with "gopkg.in/", +// this second requirement is replaced by a requirement that the path +// follow the gopkg.in server's conventions. +// Third, no path element may begin with a dot. +func CheckPath(path string) (err error) { + defer func() { + if err != nil { + err = &InvalidPathError{Kind: "module", Path: path, Err: err} + } + }() + + if err := checkPath(path, modulePath); err != nil { + return err + } + i := strings.Index(path, "/") + if i < 0 { + i = len(path) + } + if i == 0 { + return fmt.Errorf("leading slash") + } + if !strings.Contains(path[:i], ".") { + return fmt.Errorf("missing dot in first path element") + } + if path[0] == '-' { + return fmt.Errorf("leading dash in first path element") + } + for _, r := range path[:i] { + if !firstPathOK(r) { + return fmt.Errorf("invalid char %q in first path element", r) + } + } + if _, _, ok := SplitPathVersion(path); !ok { + return fmt.Errorf("invalid version") + } + return nil +} + +// CheckImportPath checks that an import path is valid. +// +// A valid import path consists of one or more valid path elements +// separated by slashes (U+002F). (It must not begin with nor end in a slash.) +// +// A valid path element is a non-empty string made up of +// ASCII letters, ASCII digits, and limited ASCII punctuation: - . _ and ~. +// It must not end with a dot (U+002E), nor contain two dots in a row. +// +// The element prefix up to the first dot must not be a reserved file name +// on Windows, regardless of case (CON, com1, NuL, and so on). The element +// must not have a suffix of a tilde followed by one or more ASCII digits +// (to exclude paths elements that look like Windows short-names). +// +// CheckImportPath may be less restrictive in the future, but see the +// top-level package documentation for additional information about +// subtleties of Unicode. +func CheckImportPath(path string) error { + if err := checkPath(path, importPath); err != nil { + return &InvalidPathError{Kind: "import", Path: path, Err: err} + } + return nil +} + +// pathKind indicates what kind of path we're checking. Module paths, +// import paths, and file paths have different restrictions. +type pathKind int + +const ( + modulePath pathKind = iota + importPath + filePath +) + +// checkPath checks that a general path is valid. kind indicates what +// specific constraints should be applied. +// +// checkPath returns an error describing why the path is not valid. +// Because these checks apply to module, import, and file paths, +// and because other checks may be applied, the caller is expected to wrap +// this error with InvalidPathError. +func checkPath(path string, kind pathKind) error { + if !utf8.ValidString(path) { + return fmt.Errorf("invalid UTF-8") + } + if path == "" { + return fmt.Errorf("empty string") + } + if path[0] == '-' && kind != filePath { + return fmt.Errorf("leading dash") + } + if strings.Contains(path, "//") { + return fmt.Errorf("double slash") + } + if path[len(path)-1] == '/' { + return fmt.Errorf("trailing slash") + } + elemStart := 0 + for i, r := range path { + if r == '/' { + if err := checkElem(path[elemStart:i], kind); err != nil { + return err + } + elemStart = i + 1 + } + } + if err := checkElem(path[elemStart:], kind); err != nil { + return err + } + return nil +} + +// checkElem checks whether an individual path element is valid. +func checkElem(elem string, kind pathKind) error { + if elem == "" { + return fmt.Errorf("empty path element") + } + if strings.Count(elem, ".") == len(elem) { + return fmt.Errorf("invalid path element %q", elem) + } + if elem[0] == '.' && kind == modulePath { + return fmt.Errorf("leading dot in path element") + } + if elem[len(elem)-1] == '.' { + return fmt.Errorf("trailing dot in path element") + } + for _, r := range elem { + ok := false + switch kind { + case modulePath: + ok = modPathOK(r) + case importPath: + ok = importPathOK(r) + case filePath: + ok = fileNameOK(r) + default: + panic(fmt.Sprintf("internal error: invalid kind %v", kind)) + } + if !ok { + return fmt.Errorf("invalid char %q", r) + } + } + + // Windows disallows a bunch of path elements, sadly. + // See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file + short := elem + if i := strings.Index(short, "."); i >= 0 { + short = short[:i] + } + for _, bad := range badWindowsNames { + if strings.EqualFold(bad, short) { + return fmt.Errorf("%q disallowed as path element component on Windows", short) + } + } + + if kind == filePath { + // don't check for Windows short-names in file names. They're + // only an issue for import paths. + return nil + } + + // Reject path components that look like Windows short-names. + // Those usually end in a tilde followed by one or more ASCII digits. + if tilde := strings.LastIndexByte(short, '~'); tilde >= 0 && tilde < len(short)-1 { + suffix := short[tilde+1:] + suffixIsDigits := true + for _, r := range suffix { + if r < '0' || r > '9' { + suffixIsDigits = false + break + } + } + if suffixIsDigits { + return fmt.Errorf("trailing tilde and digits in path element") + } + } + + return nil +} + +// CheckFilePath checks that a slash-separated file path is valid. +// The definition of a valid file path is the same as the definition +// of a valid import path except that the set of allowed characters is larger: +// all Unicode letters, ASCII digits, the ASCII space character (U+0020), +// and the ASCII punctuation characters +// “!#$%&()+,-.=@[]^_{}~”. +// (The excluded punctuation characters, " * < > ? ` ' | / \ and :, +// have special meanings in certain shells or operating systems.) +// +// CheckFilePath may be less restrictive in the future, but see the +// top-level package documentation for additional information about +// subtleties of Unicode. +func CheckFilePath(path string) error { + if err := checkPath(path, filePath); err != nil { + return &InvalidPathError{Kind: "file", Path: path, Err: err} + } + return nil +} + +// badWindowsNames are the reserved file path elements on Windows. +// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file +var badWindowsNames = []string{ + "CON", + "PRN", + "AUX", + "NUL", + "COM1", + "COM2", + "COM3", + "COM4", + "COM5", + "COM6", + "COM7", + "COM8", + "COM9", + "LPT1", + "LPT2", + "LPT3", + "LPT4", + "LPT5", + "LPT6", + "LPT7", + "LPT8", + "LPT9", +} + +// SplitPathVersion returns prefix and major version such that prefix+pathMajor == path +// and version is either empty or "/vN" for N >= 2. +// As a special case, gopkg.in paths are recognized directly; +// they require ".vN" instead of "/vN", and for all N, not just N >= 2. +// SplitPathVersion returns with ok = false when presented with +// a path whose last path element does not satisfy the constraints +// applied by CheckPath, such as "example.com/pkg/v1" or "example.com/pkg/v1.2". +func SplitPathVersion(path string) (prefix, pathMajor string, ok bool) { + if strings.HasPrefix(path, "gopkg.in/") { + return splitGopkgIn(path) + } + + i := len(path) + dot := false + for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9' || path[i-1] == '.') { + if path[i-1] == '.' { + dot = true + } + i-- + } + if i <= 1 || i == len(path) || path[i-1] != 'v' || path[i-2] != '/' { + return path, "", true + } + prefix, pathMajor = path[:i-2], path[i-2:] + if dot || len(pathMajor) <= 2 || pathMajor[2] == '0' || pathMajor == "/v1" { + return path, "", false + } + return prefix, pathMajor, true +} + +// splitGopkgIn is like SplitPathVersion but only for gopkg.in paths. +func splitGopkgIn(path string) (prefix, pathMajor string, ok bool) { + if !strings.HasPrefix(path, "gopkg.in/") { + return path, "", false + } + i := len(path) + if strings.HasSuffix(path, "-unstable") { + i -= len("-unstable") + } + for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9') { + i-- + } + if i <= 1 || path[i-1] != 'v' || path[i-2] != '.' { + // All gopkg.in paths must end in vN for some N. + return path, "", false + } + prefix, pathMajor = path[:i-2], path[i-2:] + if len(pathMajor) <= 2 || pathMajor[2] == '0' && pathMajor != ".v0" { + return path, "", false + } + return prefix, pathMajor, true +} + +// MatchPathMajor reports whether the semantic version v +// matches the path major version pathMajor. +// +// MatchPathMajor returns true if and only if CheckPathMajor returns nil. +func MatchPathMajor(v, pathMajor string) bool { + return CheckPathMajor(v, pathMajor) == nil +} + +// CheckPathMajor returns a non-nil error if the semantic version v +// does not match the path major version pathMajor. +func CheckPathMajor(v, pathMajor string) error { + // TODO(jayconrod): return errors or panic for invalid inputs. This function + // (and others) was covered by integration tests for cmd/go, and surrounding + // code protected against invalid inputs like non-canonical versions. + if strings.HasPrefix(pathMajor, ".v") && strings.HasSuffix(pathMajor, "-unstable") { + pathMajor = strings.TrimSuffix(pathMajor, "-unstable") + } + if strings.HasPrefix(v, "v0.0.0-") && pathMajor == ".v1" { + // Allow old bug in pseudo-versions that generated v0.0.0- pseudoversion for gopkg .v1. + // For example, gopkg.in/yaml.v2@v2.2.1's go.mod requires gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405. + return nil + } + m := semver.Major(v) + if pathMajor == "" { + if m == "v0" || m == "v1" || semver.Build(v) == "+incompatible" { + return nil + } + pathMajor = "v0 or v1" + } else if pathMajor[0] == '/' || pathMajor[0] == '.' { + if m == pathMajor[1:] { + return nil + } + pathMajor = pathMajor[1:] + } + return &InvalidVersionError{ + Version: v, + Err: fmt.Errorf("should be %s, not %s", pathMajor, semver.Major(v)), + } +} + +// PathMajorPrefix returns the major-version tag prefix implied by pathMajor. +// An empty PathMajorPrefix allows either v0 or v1. +// +// Note that MatchPathMajor may accept some versions that do not actually begin +// with this prefix: namely, it accepts a 'v0.0.0-' prefix for a '.v1' +// pathMajor, even though that pathMajor implies 'v1' tagging. +func PathMajorPrefix(pathMajor string) string { + if pathMajor == "" { + return "" + } + if pathMajor[0] != '/' && pathMajor[0] != '.' { + panic("pathMajor suffix " + pathMajor + " passed to PathMajorPrefix lacks separator") + } + if strings.HasPrefix(pathMajor, ".v") && strings.HasSuffix(pathMajor, "-unstable") { + pathMajor = strings.TrimSuffix(pathMajor, "-unstable") + } + m := pathMajor[1:] + if m != semver.Major(m) { + panic("pathMajor suffix " + pathMajor + "passed to PathMajorPrefix is not a valid major version") + } + return m +} + +// CanonicalVersion returns the canonical form of the version string v. +// It is the same as semver.Canonical(v) except that it preserves the special build suffix "+incompatible". +func CanonicalVersion(v string) string { + cv := semver.Canonical(v) + if semver.Build(v) == "+incompatible" { + cv += "+incompatible" + } + return cv +} + +// Sort sorts the list by Path, breaking ties by comparing Version fields. +// The Version fields are interpreted as semantic versions (using semver.Compare) +// optionally followed by a tie-breaking suffix introduced by a slash character, +// like in "v0.0.1/go.mod". +func Sort(list []Version) { + sort.Slice(list, func(i, j int) bool { + mi := list[i] + mj := list[j] + if mi.Path != mj.Path { + return mi.Path < mj.Path + } + // To help go.sum formatting, allow version/file. + // Compare semver prefix by semver rules, + // file by string order. + vi := mi.Version + vj := mj.Version + var fi, fj string + if k := strings.Index(vi, "/"); k >= 0 { + vi, fi = vi[:k], vi[k:] + } + if k := strings.Index(vj, "/"); k >= 0 { + vj, fj = vj[:k], vj[k:] + } + if vi != vj { + return semver.Compare(vi, vj) < 0 + } + return fi < fj + }) +} + +// EscapePath returns the escaped form of the given module path. +// It fails if the module path is invalid. +func EscapePath(path string) (escaped string, err error) { + if err := CheckPath(path); err != nil { + return "", err + } + + return escapeString(path) +} + +// EscapeVersion returns the escaped form of the given module version. +// Versions are allowed to be in non-semver form but must be valid file names +// and not contain exclamation marks. +func EscapeVersion(v string) (escaped string, err error) { + if err := checkElem(v, filePath); err != nil || strings.Contains(v, "!") { + return "", &InvalidVersionError{ + Version: v, + Err: fmt.Errorf("disallowed version string"), + } + } + return escapeString(v) +} + +func escapeString(s string) (escaped string, err error) { + haveUpper := false + for _, r := range s { + if r == '!' || r >= utf8.RuneSelf { + // This should be disallowed by CheckPath, but diagnose anyway. + // The correctness of the escaping loop below depends on it. + return "", fmt.Errorf("internal error: inconsistency in EscapePath") + } + if 'A' <= r && r <= 'Z' { + haveUpper = true + } + } + + if !haveUpper { + return s, nil + } + + var buf []byte + for _, r := range s { + if 'A' <= r && r <= 'Z' { + buf = append(buf, '!', byte(r+'a'-'A')) + } else { + buf = append(buf, byte(r)) + } + } + return string(buf), nil +} + +// UnescapePath returns the module path for the given escaped path. +// It fails if the escaped path is invalid or describes an invalid path. +func UnescapePath(escaped string) (path string, err error) { + path, ok := unescapeString(escaped) + if !ok { + return "", fmt.Errorf("invalid escaped module path %q", escaped) + } + if err := CheckPath(path); err != nil { + return "", fmt.Errorf("invalid escaped module path %q: %v", escaped, err) + } + return path, nil +} + +// UnescapeVersion returns the version string for the given escaped version. +// It fails if the escaped form is invalid or describes an invalid version. +// Versions are allowed to be in non-semver form but must be valid file names +// and not contain exclamation marks. +func UnescapeVersion(escaped string) (v string, err error) { + v, ok := unescapeString(escaped) + if !ok { + return "", fmt.Errorf("invalid escaped version %q", escaped) + } + if err := checkElem(v, filePath); err != nil { + return "", fmt.Errorf("invalid escaped version %q: %v", v, err) + } + return v, nil +} + +func unescapeString(escaped string) (string, bool) { + var buf []byte + + bang := false + for _, r := range escaped { + if r >= utf8.RuneSelf { + return "", false + } + if bang { + bang = false + if r < 'a' || 'z' < r { + return "", false + } + buf = append(buf, byte(r+'A'-'a')) + continue + } + if r == '!' { + bang = true + continue + } + if 'A' <= r && r <= 'Z' { + return "", false + } + buf = append(buf, byte(r)) + } + if bang { + return "", false + } + return string(buf), true +} + +// MatchPrefixPatterns reports whether any path prefix of target matches one of +// the glob patterns (as defined by path.Match) in the comma-separated globs +// list. This implements the algorithm used when matching a module path to the +// GOPRIVATE environment variable, as described by 'go help module-private'. +// +// It ignores any empty or malformed patterns in the list. +// Trailing slashes on patterns are ignored. +func MatchPrefixPatterns(globs, target string) bool { + for globs != "" { + // Extract next non-empty glob in comma-separated list. + var glob string + if i := strings.Index(globs, ","); i >= 0 { + glob, globs = globs[:i], globs[i+1:] + } else { + glob, globs = globs, "" + } + glob = strings.TrimSuffix(glob, "/") + if glob == "" { + continue + } + + // A glob with N+1 path elements (N slashes) needs to be matched + // against the first N+1 path elements of target, + // which end just before the N+1'th slash. + n := strings.Count(glob, "/") + prefix := target + // Walk target, counting slashes, truncating at the N+1'th slash. + for i := 0; i < len(target); i++ { + if target[i] == '/' { + if n == 0 { + prefix = target[:i] + break + } + n-- + } + } + if n > 0 { + // Not enough prefix elements. + continue + } + matched, _ := path.Match(glob, prefix) + if matched { + return true + } + } + return false +} |