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// 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 packages
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"log"
"os"
"os/exec"
"path/filepath"
"regexp"
"strings"
"sync"
"golang.org/x/tools/internal/gopathwalk"
"golang.org/x/tools/internal/semver"
)
// A goTooOldError reports that the go command
// found by exec.LookPath is too old to use the new go list behavior.
type goTooOldError struct {
error
}
// goListDriver uses the go list command to interpret the patterns and produce
// the build system package structure.
// See driver for more details.
func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
// Determine files requested in contains patterns
var containFiles []string
var packagesNamed []string
restPatterns := make([]string, 0, len(patterns))
// Extract file= and other [querytype]= patterns. Report an error if querytype
// doesn't exist.
extractQueries:
for _, pattern := range patterns {
eqidx := strings.Index(pattern, "=")
if eqidx < 0 {
restPatterns = append(restPatterns, pattern)
} else {
query, value := pattern[:eqidx], pattern[eqidx+len("="):]
switch query {
case "file":
containFiles = append(containFiles, value)
case "pattern":
restPatterns = append(restPatterns, value)
case "name":
packagesNamed = append(packagesNamed, value)
case "": // not a reserved query
restPatterns = append(restPatterns, pattern)
default:
for _, rune := range query {
if rune < 'a' || rune > 'z' { // not a reserved query
restPatterns = append(restPatterns, pattern)
continue extractQueries
}
}
// Reject all other patterns containing "="
return nil, fmt.Errorf("invalid query type %q in query pattern %q", query, pattern)
}
}
}
patterns = restPatterns
// Look for the deprecated contains: syntax.
// TODO(matloob): delete this around mid-October 2018.
restPatterns = restPatterns[:0]
for _, pattern := range patterns {
if strings.HasPrefix(pattern, "contains:") {
containFile := strings.TrimPrefix(pattern, "contains:")
containFiles = append(containFiles, containFile)
} else {
restPatterns = append(restPatterns, pattern)
}
}
containFiles = absJoin(cfg.Dir, containFiles)
// TODO(matloob): Remove the definition of listfunc and just use golistPackages once go1.12 is released.
var listfunc driver
listfunc = func(cfg *Config, words ...string) (*driverResponse, error) {
response, err := golistDriverCurrent(cfg, words...)
if _, ok := err.(goTooOldError); ok {
listfunc = golistDriverFallback
return listfunc(cfg, words...)
}
listfunc = golistDriverCurrent
return response, err
}
var response *driverResponse
var err error
// see if we have any patterns to pass through to go list.
if len(restPatterns) > 0 {
response, err = listfunc(cfg, restPatterns...)
if err != nil {
return nil, err
}
} else {
response = &driverResponse{}
}
if len(containFiles) == 0 && len(packagesNamed) == 0 {
return response, nil
}
seenPkgs := make(map[string]*Package) // for deduplication. different containing queries could produce same packages
for _, pkg := range response.Packages {
seenPkgs[pkg.ID] = pkg
}
addPkg := func(p *Package) {
if _, ok := seenPkgs[p.ID]; ok {
return
}
seenPkgs[p.ID] = p
response.Packages = append(response.Packages, p)
}
containsResults, err := runContainsQueries(cfg, listfunc, addPkg, containFiles)
if err != nil {
return nil, err
}
response.Roots = append(response.Roots, containsResults...)
namedResults, err := runNamedQueries(cfg, listfunc, addPkg, packagesNamed)
if err != nil {
return nil, err
}
response.Roots = append(response.Roots, namedResults...)
return response, nil
}
func runContainsQueries(cfg *Config, driver driver, addPkg func(*Package), queries []string) ([]string, error) {
var results []string
for _, query := range queries {
// TODO(matloob): Do only one query per directory.
fdir := filepath.Dir(query)
cfg.Dir = fdir
dirResponse, err := driver(cfg, ".")
if err != nil {
return nil, err
}
isRoot := make(map[string]bool, len(dirResponse.Roots))
for _, root := range dirResponse.Roots {
isRoot[root] = true
}
for _, pkg := range dirResponse.Packages {
// Add any new packages to the main set
// We don't bother to filter packages that will be dropped by the changes of roots,
// that will happen anyway during graph construction outside this function.
// Over-reporting packages is not a problem.
addPkg(pkg)
// if the package was not a root one, it cannot have the file
if !isRoot[pkg.ID] {
continue
}
for _, pkgFile := range pkg.GoFiles {
if filepath.Base(query) == filepath.Base(pkgFile) {
results = append(results, pkg.ID)
break
}
}
}
}
return results, nil
}
// modCacheRegexp splits a path in a module cache into module, module version, and package.
var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
func runNamedQueries(cfg *Config, driver driver, addPkg func(*Package), queries []string) ([]string, error) {
// Determine which directories are relevant to scan.
roots, modRoot, err := roots(cfg)
if err != nil {
return nil, err
}
// Scan the selected directories. Simple matches, from GOPATH/GOROOT
// or the local module, can simply be "go list"ed. Matches from the
// module cache need special treatment.
var matchesMu sync.Mutex
var simpleMatches, modCacheMatches []string
add := func(root gopathwalk.Root, dir string) {
// Walk calls this concurrently; protect the result slices.
matchesMu.Lock()
defer matchesMu.Unlock()
path := dir[len(root.Path)+1:]
if pathMatchesQueries(path, queries) {
switch root.Type {
case gopathwalk.RootModuleCache:
modCacheMatches = append(modCacheMatches, path)
case gopathwalk.RootCurrentModule:
// We'd need to read go.mod to find the full
// import path. Relative's easier.
rel, err := filepath.Rel(cfg.Dir, dir)
if err != nil {
// This ought to be impossible, since
// we found dir in the current module.
panic(err)
}
simpleMatches = append(simpleMatches, "./"+rel)
case gopathwalk.RootGOPATH, gopathwalk.RootGOROOT:
simpleMatches = append(simpleMatches, path)
}
}
}
gopathwalk.Walk(roots, add, gopathwalk.Options{ModulesEnabled: modRoot != ""})
// Weird special case: the top-level package in a module will be in
// whatever directory the user checked the repository out into. It's
// more reasonable for that to not match the package name. So, if there
// are any Go files in the mod root, query it just to be safe.
if modRoot != "" {
rel, err := filepath.Rel(cfg.Dir, modRoot)
if err != nil {
panic(err) // See above.
}
files, err := ioutil.ReadDir(modRoot)
for _, f := range files {
if strings.HasSuffix(f.Name(), ".go") {
simpleMatches = append(simpleMatches, rel)
break
}
}
}
var results []string
addResponse := func(r *driverResponse) {
for _, pkg := range r.Packages {
addPkg(pkg)
for _, name := range queries {
if pkg.Name == name {
results = append(results, pkg.ID)
break
}
}
}
}
if len(simpleMatches) != 0 {
resp, err := driver(cfg, simpleMatches...)
if err != nil {
return nil, err
}
addResponse(resp)
}
// Module cache matches are tricky. We want to avoid downloading new
// versions of things, so we need to use the ones present in the cache.
// go list doesn't accept version specifiers, so we have to write out a
// temporary module, and do the list in that module.
if len(modCacheMatches) != 0 {
// Collect all the matches, deduplicating by major version
// and preferring the newest.
type modInfo struct {
mod string
major string
}
mods := make(map[modInfo]string)
var imports []string
for _, modPath := range modCacheMatches {
matches := modCacheRegexp.FindStringSubmatch(modPath)
mod, ver := filepath.ToSlash(matches[1]), matches[2]
importPath := filepath.ToSlash(filepath.Join(matches[1], matches[3]))
major := semver.Major(ver)
if prevVer, ok := mods[modInfo{mod, major}]; !ok || semver.Compare(ver, prevVer) > 0 {
mods[modInfo{mod, major}] = ver
}
imports = append(imports, importPath)
}
// Build the temporary module.
var gomod bytes.Buffer
gomod.WriteString("module modquery\nrequire (\n")
for mod, version := range mods {
gomod.WriteString("\t" + mod.mod + " " + version + "\n")
}
gomod.WriteString(")\n")
tmpCfg := *cfg
var err error
tmpCfg.Dir, err = ioutil.TempDir("", "gopackages-modquery")
if err != nil {
return nil, err
}
defer os.RemoveAll(tmpCfg.Dir)
if err := ioutil.WriteFile(filepath.Join(tmpCfg.Dir, "go.mod"), gomod.Bytes(), 0777); err != nil {
return nil, fmt.Errorf("writing go.mod for module cache query: %v", err)
}
// Run the query, using the import paths calculated from the matches above.
resp, err := driver(&tmpCfg, imports...)
if err != nil {
return nil, fmt.Errorf("querying module cache matches: %v", err)
}
addResponse(resp)
}
return results, nil
}
// roots selects the appropriate paths to walk based on the passed-in configuration,
// particularly the environment and the presence of a go.mod in cfg.Dir's parents.
func roots(cfg *Config) ([]gopathwalk.Root, string, error) {
stdout, err := invokeGo(cfg, "env", "GOROOT", "GOPATH", "GOMOD")
if err != nil {
return nil, "", err
}
fields := strings.Split(stdout.String(), "\n")
if len(fields) != 4 || len(fields[3]) != 0 {
return nil, "", fmt.Errorf("go env returned unexpected output: %q", stdout.String())
}
goroot, gopath, gomod := fields[0], filepath.SplitList(fields[1]), fields[2]
var modDir string
if gomod != "" {
modDir = filepath.Dir(gomod)
}
var roots []gopathwalk.Root
// Always add GOROOT.
roots = append(roots, gopathwalk.Root{filepath.Join(goroot, "/src"), gopathwalk.RootGOROOT})
// If modules are enabled, scan the module dir.
if modDir != "" {
roots = append(roots, gopathwalk.Root{modDir, gopathwalk.RootCurrentModule})
}
// Add either GOPATH/src or GOPATH/pkg/mod, depending on module mode.
for _, p := range gopath {
if modDir != "" {
roots = append(roots, gopathwalk.Root{filepath.Join(p, "/pkg/mod"), gopathwalk.RootModuleCache})
} else {
roots = append(roots, gopathwalk.Root{filepath.Join(p, "/src"), gopathwalk.RootGOPATH})
}
}
return roots, modDir, nil
}
// These functions were copied from goimports. See further documentation there.
// pathMatchesQueries is adapted from pkgIsCandidate.
// TODO: is it reasonable to do Contains here, rather than an exact match on a path component?
func pathMatchesQueries(path string, queries []string) bool {
lastTwo := lastTwoComponents(path)
for _, query := range queries {
if strings.Contains(lastTwo, query) {
return true
}
if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(query) {
lastTwo = lowerASCIIAndRemoveHyphen(lastTwo)
if strings.Contains(lastTwo, query) {
return true
}
}
}
return false
}
// lastTwoComponents returns at most the last two path components
// of v, using either / or \ as the path separator.
func lastTwoComponents(v string) string {
nslash := 0
for i := len(v) - 1; i >= 0; i-- {
if v[i] == '/' || v[i] == '\\' {
nslash++
if nslash == 2 {
return v[i:]
}
}
}
return v
}
func hasHyphenOrUpperASCII(s string) bool {
for i := 0; i < len(s); i++ {
b := s[i]
if b == '-' || ('A' <= b && b <= 'Z') {
return true
}
}
return false
}
func lowerASCIIAndRemoveHyphen(s string) (ret string) {
buf := make([]byte, 0, len(s))
for i := 0; i < len(s); i++ {
b := s[i]
switch {
case b == '-':
continue
case 'A' <= b && b <= 'Z':
buf = append(buf, b+('a'-'A'))
default:
buf = append(buf, b)
}
}
return string(buf)
}
// Fields must match go list;
// see $GOROOT/src/cmd/go/internal/load/pkg.go.
type jsonPackage struct {
ImportPath string
Dir string
Name string
Export string
GoFiles []string
CompiledGoFiles []string
CFiles []string
CgoFiles []string
CXXFiles []string
MFiles []string
HFiles []string
FFiles []string
SFiles []string
SwigFiles []string
SwigCXXFiles []string
SysoFiles []string
Imports []string
ImportMap map[string]string
Deps []string
TestGoFiles []string
TestImports []string
XTestGoFiles []string
XTestImports []string
ForTest string // q in a "p [q.test]" package, else ""
DepOnly bool
Error *jsonPackageError
}
type jsonPackageError struct {
ImportStack []string
Pos string
Err string
}
func otherFiles(p *jsonPackage) [][]string {
return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles}
}
// golistDriverCurrent uses the "go list" command to expand the
// pattern words and return metadata for the specified packages.
// dir may be "" and env may be nil, as per os/exec.Command.
func golistDriverCurrent(cfg *Config, words ...string) (*driverResponse, error) {
// go list uses the following identifiers in ImportPath and Imports:
//
// "p" -- importable package or main (command)
// "q.test" -- q's test executable
// "p [q.test]" -- variant of p as built for q's test executable
// "q_test [q.test]" -- q's external test package
//
// The packages p that are built differently for a test q.test
// are q itself, plus any helpers used by the external test q_test,
// typically including "testing" and all its dependencies.
// Run "go list" for complete
// information on the specified packages.
buf, err := invokeGo(cfg, golistargs(cfg, words)...)
if err != nil {
return nil, err
}
// Decode the JSON and convert it to Package form.
var response driverResponse
for dec := json.NewDecoder(buf); dec.More(); {
p := new(jsonPackage)
if err := dec.Decode(p); err != nil {
return nil, fmt.Errorf("JSON decoding failed: %v", err)
}
if p.ImportPath == "" {
// The documentation for go list says that “[e]rroneous packages will have
// a non-empty ImportPath”. If for some reason it comes back empty, we
// prefer to error out rather than silently discarding data or handing
// back a package without any way to refer to it.
if p.Error != nil {
return nil, Error{
Pos: p.Error.Pos,
Msg: p.Error.Err,
}
}
return nil, fmt.Errorf("package missing import path: %+v", p)
}
pkg := &Package{
Name: p.Name,
ID: p.ImportPath,
GoFiles: absJoin(p.Dir, p.GoFiles, p.CgoFiles),
CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
OtherFiles: absJoin(p.Dir, otherFiles(p)...),
}
// Extract the PkgPath from the package's ID.
if i := strings.IndexByte(pkg.ID, ' '); i >= 0 {
pkg.PkgPath = pkg.ID[:i]
} else {
pkg.PkgPath = pkg.ID
}
if pkg.PkgPath == "unsafe" {
pkg.GoFiles = nil // ignore fake unsafe.go file
}
// Assume go list emits only absolute paths for Dir.
if p.Dir != "" && !filepath.IsAbs(p.Dir) {
log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir)
}
if p.Export != "" && !filepath.IsAbs(p.Export) {
pkg.ExportFile = filepath.Join(p.Dir, p.Export)
} else {
pkg.ExportFile = p.Export
}
// imports
//
// Imports contains the IDs of all imported packages.
// ImportsMap records (path, ID) only where they differ.
ids := make(map[string]bool)
for _, id := range p.Imports {
ids[id] = true
}
pkg.Imports = make(map[string]*Package)
for path, id := range p.ImportMap {
pkg.Imports[path] = &Package{ID: id} // non-identity import
delete(ids, id)
}
for id := range ids {
if id == "C" {
continue
}
pkg.Imports[id] = &Package{ID: id} // identity import
}
if !p.DepOnly {
response.Roots = append(response.Roots, pkg.ID)
}
// TODO(matloob): Temporary hack since CompiledGoFiles isn't always set.
if len(pkg.CompiledGoFiles) == 0 {
pkg.CompiledGoFiles = pkg.GoFiles
}
if p.Error != nil {
pkg.Errors = append(pkg.Errors, Error{
Pos: p.Error.Pos,
Msg: p.Error.Err,
})
}
response.Packages = append(response.Packages, pkg)
}
return &response, nil
}
// absJoin absolutizes and flattens the lists of files.
func absJoin(dir string, fileses ...[]string) (res []string) {
for _, files := range fileses {
for _, file := range files {
if !filepath.IsAbs(file) {
file = filepath.Join(dir, file)
}
res = append(res, file)
}
}
return res
}
func golistargs(cfg *Config, words []string) []string {
fullargs := []string{
"list", "-e", "-json", "-compiled",
fmt.Sprintf("-test=%t", cfg.Tests),
fmt.Sprintf("-export=%t", usesExportData(cfg)),
fmt.Sprintf("-deps=%t", cfg.Mode >= LoadImports),
}
fullargs = append(fullargs, cfg.BuildFlags...)
fullargs = append(fullargs, "--")
fullargs = append(fullargs, words...)
return fullargs
}
// invokeGo returns the stdout of a go command invocation.
func invokeGo(cfg *Config, args ...string) (*bytes.Buffer, error) {
stdout := new(bytes.Buffer)
stderr := new(bytes.Buffer)
cmd := exec.CommandContext(cfg.Context, "go", args...)
// On darwin the cwd gets resolved to the real path, which breaks anything that
// expects the working directory to keep the original path, including the
// go command when dealing with modules.
// The Go stdlib has a special feature where if the cwd and the PWD are the
// same node then it trusts the PWD, so by setting it in the env for the child
// process we fix up all the paths returned by the go command.
cmd.Env = append(append([]string{}, cfg.Env...), "PWD="+cfg.Dir)
cmd.Dir = cfg.Dir
cmd.Stdout = stdout
cmd.Stderr = stderr
if err := cmd.Run(); err != nil {
exitErr, ok := err.(*exec.ExitError)
if !ok {
// Catastrophic error:
// - executable not found
// - context cancellation
return nil, fmt.Errorf("couldn't exec 'go %v': %s %T", args, err, err)
}
// Old go version?
if strings.Contains(stderr.String(), "flag provided but not defined") {
return nil, goTooOldError{fmt.Errorf("unsupported version of go: %s: %s", exitErr, stderr)}
}
// Export mode entails a build.
// If that build fails, errors appear on stderr
// (despite the -e flag) and the Export field is blank.
// Do not fail in that case.
if !usesExportData(cfg) {
return nil, fmt.Errorf("go %v: %s: %s", args, exitErr, stderr)
}
}
// As of writing, go list -export prints some non-fatal compilation
// errors to stderr, even with -e set. We would prefer that it put
// them in the Package.Error JSON (see http://golang.org/issue/26319).
// In the meantime, there's nowhere good to put them, but they can
// be useful for debugging. Print them if $GOPACKAGESPRINTGOLISTERRORS
// is set.
if len(stderr.Bytes()) != 0 && os.Getenv("GOPACKAGESPRINTGOLISTERRORS") != "" {
fmt.Fprintf(os.Stderr, "go %v stderr: <<%s>>\n", args, stderr)
}
// debugging
if false {
fmt.Fprintf(os.Stderr, "go %v stdout: <<%s>>\n", args, stdout)
}
return stdout, nil
}