go/build: add AllTags to Package

AllTags lists all the tags that can affect the decision
about which files to include. Tools scanning packages
can use this to decide how many variants there are
and what they are.

R=bradfitz
CC=golang-dev
https://golang.org/cl/12703044

diff --git a/src/pkg/go/build/build.go b/src/pkg/go/build/build.go
index 38de9ba07f70738e79892dd5a064c73a7225f829..563e7fe21b8a9ce49aafb5756425e9aba7ee6ca9 100644 (file)
--- a/src/pkg/go/build/build.go
+++ b/src/pkg/go/build/build.go
@@ -337,16 +337,17 @@ const (
 
 // A Package describes the Go package found in a directory.
 type Package struct {
-       Dir        string // directory containing package sources
-       Name       string // package name
-       Doc        string // documentation synopsis
-       ImportPath string // import path of package ("" if unknown)
-       Root       string // root of Go tree where this package lives
-       SrcRoot    string // package source root directory ("" if unknown)
-       PkgRoot    string // package install root directory ("" if unknown)
-       BinDir     string // command install directory ("" if unknown)
-       Goroot     bool   // package found in Go root
-       PkgObj     string // installed .a file
+       Dir        string   // directory containing package sources
+       Name       string   // package name
+       Doc        string   // documentation synopsis
+       ImportPath string   // import path of package ("" if unknown)
+       Root       string   // root of Go tree where this package lives
+       SrcRoot    string   // package source root directory ("" if unknown)
+       PkgRoot    string   // package install root directory ("" if unknown)
+       BinDir     string   // command install directory ("" if unknown)
+       Goroot     bool     // package found in Go root
+       PkgObj     string   // installed .a file
+       AllTags    []string // tags that can influence file selection in this directory
 
        // Source files
        GoFiles        []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
@@ -578,6 +579,7 @@ Found:
        imported := make(map[string][]token.Position)
        testImported := make(map[string][]token.Position)
        xTestImported := make(map[string][]token.Position)
+       allTags := make(map[string]bool)
        fset := token.NewFileSet()
        for _, d := range dirs {
                if d.IsDir() {
@@ -595,7 +597,7 @@ Found:
                }
                ext := name[i:]
 
-               if !ctxt.UseAllFiles && !ctxt.goodOSArchFile(name) {
+               if !ctxt.goodOSArchFile(name, allTags) && !ctxt.UseAllFiles {
                        if ext == ".go" {
                                p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
                        }
@@ -634,7 +636,7 @@ Found:
                }
 
                // Look for +build comments to accept or reject the file.
-               if !ctxt.UseAllFiles && !ctxt.shouldBuild(data) {
+               if !ctxt.shouldBuild(data, allTags) && !ctxt.UseAllFiles {
                        if ext == ".go" {
                                p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
                        }
@@ -736,6 +738,7 @@ Found:
                        }
                }
                if isCgo {
+                       allTags["cgo"] = true
                        if ctxt.CgoEnabled {
                                p.CgoFiles = append(p.CgoFiles, name)
                        }
@@ -751,6 +754,11 @@ Found:
                return p, &NoGoError{p.Dir}
        }
 
+       for tag := range allTags {
+               p.AllTags = append(p.AllTags, tag)
+       }
+       sort.Strings(p.AllTags)
+
        p.Imports, p.ImportPos = cleanImports(imported)
        p.TestImports, p.TestImportPos = cleanImports(testImported)
        p.XTestImports, p.XTestImportPos = cleanImports(xTestImported)
@@ -800,7 +808,7 @@ var slashslash = []byte("//")
 //
 // marks the file as applicable only on Windows and Linux.
 //
-func (ctxt *Context) shouldBuild(content []byte) bool {
+func (ctxt *Context) shouldBuild(content []byte, allTags map[string]bool) bool {
        // Pass 1. Identify leading run of // comments and blank lines,
        // which must be followed by a blank line.
        end := 0
@@ -825,6 +833,7 @@ func (ctxt *Context) shouldBuild(content []byte) bool {
 
        // Pass 2.  Process each line in the run.
        p = content
+       allok := true
        for len(p) > 0 {
                line := p
                if i := bytes.IndexByte(line, '\n'); i >= 0 {
@@ -841,19 +850,19 @@ func (ctxt *Context) shouldBuild(content []byte) bool {
                                if f[0] == "+build" {
                                        ok := false
                                        for _, tok := range f[1:] {
-                                               if ctxt.match(tok) {
+                                               if ctxt.match(tok, allTags) {
                                                        ok = true
-                                                       break
                                                }
                                        }
                                        if !ok {
-                                               return false // this one doesn't match
+                                               allok = false
                                        }
                                }
                        }
                }
        }
-       return true // everything matches
+
+       return allok
 }
 
 // saveCgo saves the information from the #cgo lines in the import "C" comment.
@@ -893,7 +902,7 @@ func (ctxt *Context) saveCgo(filename string, di *Package, cg *ast.CommentGroup)
                if len(cond) > 0 {
                        ok := false
                        for _, c := range cond {
-                               if ctxt.match(c) {
+                               if ctxt.match(c, nil) {
                                        ok = true
                                        break
                                }
@@ -1018,19 +1027,28 @@ func splitQuoted(s string) (r []string, err error) {
 //     !tag (if tag is not listed in ctxt.BuildTags or ctxt.ReleaseTags)
 //     a comma-separated list of any of these
 //
-func (ctxt *Context) match(name string) bool {
+func (ctxt *Context) match(name string, allTags map[string]bool) bool {
        if name == "" {
+               if allTags != nil {
+                       allTags[name] = true
+               }
                return false
        }
        if i := strings.Index(name, ","); i >= 0 {
                // comma-separated list
-               return ctxt.match(name[:i]) && ctxt.match(name[i+1:])
+               ok1 := ctxt.match(name[:i], allTags)
+               ok2 := ctxt.match(name[i+1:], allTags)
+               return ok1 && ok2
        }
        if strings.HasPrefix(name, "!!") { // bad syntax, reject always
                return false
        }
        if strings.HasPrefix(name, "!") { // negation
-               return len(name) > 1 && !ctxt.match(name[1:])
+               return len(name) > 1 && !ctxt.match(name[1:], allTags)
+       }
+
+       if allTags != nil {
+               allTags[name] = true
        }
 
        // Tags must be letters, digits, underscores or dots.
@@ -1075,7 +1093,7 @@ func (ctxt *Context) match(name string) bool {
 //     name_$(GOARCH)_test.*
 //     name_$(GOOS)_$(GOARCH)_test.*
 //
-func (ctxt *Context) goodOSArchFile(name string) bool {
+func (ctxt *Context) goodOSArchFile(name string, allTags map[string]bool) bool {
        if dot := strings.Index(name, "."); dot != -1 {
                name = name[:dot]
        }
@@ -1085,12 +1103,16 @@ func (ctxt *Context) goodOSArchFile(name string) bool {
        }
        n := len(l)
        if n >= 2 && knownOS[l[n-2]] && knownArch[l[n-1]] {
+               allTags[l[n-2]] = true
+               allTags[l[n-1]] = true
                return l[n-2] == ctxt.GOOS && l[n-1] == ctxt.GOARCH
        }
        if n >= 1 && knownOS[l[n-1]] {
+               allTags[l[n-1]] = true
                return l[n-1] == ctxt.GOOS
        }
        if n >= 1 && knownArch[l[n-1]] {
+               allTags[l[n-1]] = true
                return l[n-1] == ctxt.GOARCH
        }
        return true

diff --git a/src/pkg/go/build/build_test.go b/src/pkg/go/build/build_test.go
index d8cf98840d71f33ec435ce2f3cf2d13699661294..e36048edec925aa368c1843ccee8d2d24958639e 100644 (file)
--- a/src/pkg/go/build/build_test.go
+++ b/src/pkg/go/build/build_test.go
@@ -7,6 +7,7 @@ package build
 import (
        "os"
        "path/filepath"
+       "reflect"
        "runtime"
        "testing"
 )
@@ -14,29 +15,37 @@ import (
 func TestMatch(t *testing.T) {
        ctxt := Default
        what := "default"
-       match := func(tag string) {
-               if !ctxt.match(tag) {
+       match := func(tag string, want map[string]bool) {
+               m := make(map[string]bool)
+               if !ctxt.match(tag, m) {
                        t.Errorf("%s context should match %s, does not", what, tag)
                }
+               if !reflect.DeepEqual(m, want) {
+                       t.Errorf("%s tags = %v, want %v", tag, m, want)
+               }
        }
-       nomatch := func(tag string) {
-               if ctxt.match(tag) {
+       nomatch := func(tag string, want map[string]bool) {
+               m := make(map[string]bool)
+               if ctxt.match(tag, m) {
                        t.Errorf("%s context should NOT match %s, does", what, tag)
                }
+               if !reflect.DeepEqual(m, want) {
+                       t.Errorf("%s tags = %v, want %v", tag, m, want)
+               }
        }
 
-       match(runtime.GOOS + "," + runtime.GOARCH)
-       match(runtime.GOOS + "," + runtime.GOARCH + ",!foo")
-       nomatch(runtime.GOOS + "," + runtime.GOARCH + ",foo")
+       match(runtime.GOOS+","+runtime.GOARCH, map[string]bool{runtime.GOOS: true, runtime.GOARCH: true})
+       match(runtime.GOOS+","+runtime.GOARCH+",!foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})
+       nomatch(runtime.GOOS+","+runtime.GOARCH+",foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})
 
        what = "modified"
        ctxt.BuildTags = []string{"foo"}
-       match(runtime.GOOS + "," + runtime.GOARCH)
-       match(runtime.GOOS + "," + runtime.GOARCH + ",foo")
-       nomatch(runtime.GOOS + "," + runtime.GOARCH + ",!foo")
-       match(runtime.GOOS + "," + runtime.GOARCH + ",!bar")
-       nomatch(runtime.GOOS + "," + runtime.GOARCH + ",bar")
-       nomatch("!")
+       match(runtime.GOOS+","+runtime.GOARCH, map[string]bool{runtime.GOOS: true, runtime.GOARCH: true})
+       match(runtime.GOOS+","+runtime.GOARCH+",foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})
+       nomatch(runtime.GOOS+","+runtime.GOARCH+",!foo", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "foo": true})
+       match(runtime.GOOS+","+runtime.GOARCH+",!bar", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "bar": true})
+       nomatch(runtime.GOOS+","+runtime.GOARCH+",bar", map[string]bool{runtime.GOOS: true, runtime.GOARCH: true, "bar": true})
+       nomatch("!", map[string]bool{})
 }
 
 func TestDotSlashImport(t *testing.T) {
@@ -92,28 +101,44 @@ func TestLocalDirectory(t *testing.T) {
 func TestShouldBuild(t *testing.T) {
        const file1 = "// +build tag1\n\n" +
                "package main\n"
+       want1 := map[string]bool{"tag1": true}
 
        const file2 = "// +build cgo\n\n" +
                "// This package implements parsing of tags like\n" +
                "// +build tag1\n" +
                "package build"
+       want2 := map[string]bool{"cgo": true}
 
        const file3 = "// Copyright The Go Authors.\n\n" +
                "package build\n\n" +
                "// shouldBuild checks tags given by lines of the form\n" +
                "// +build tag\n" +
                "func shouldBuild(content []byte)\n"
+       want3 := map[string]bool{}
 
        ctx := &Context{BuildTags: []string{"tag1"}}
-       if !ctx.shouldBuild([]byte(file1)) {
-               t.Errorf("should not build file1, expected the contrary")
+       m := map[string]bool{}
+       if !ctx.shouldBuild([]byte(file1), m) {
+               t.Errorf("shouldBuild(file1) = false, want true")
+       }
+       if !reflect.DeepEqual(m, want1) {
+               t.Errorf("shoudBuild(file1) tags = %v, want %v", m, want1)
        }
-       if ctx.shouldBuild([]byte(file2)) {
-               t.Errorf("should build file2, expected the contrary")
+
+       m = map[string]bool{}
+       if ctx.shouldBuild([]byte(file2), m) {
+               t.Errorf("shouldBuild(file2) = true, want fakse")
+       }
+       if !reflect.DeepEqual(m, want2) {
+               t.Errorf("shoudBuild(file2) tags = %v, want %v", m, want2)
        }
 
+       m = map[string]bool{}
        ctx = &Context{BuildTags: nil}
-       if !ctx.shouldBuild([]byte(file3)) {
-               t.Errorf("should not build file3, expected the contrary")
+       if !ctx.shouldBuild([]byte(file3), m) {
+               t.Errorf("shouldBuild(file3) = false, want true")
+       }
+       if !reflect.DeepEqual(m, want3) {
+               t.Errorf("shoudBuild(file3) tags = %v, want %v", m, want3)
        }
 }

diff --git a/src/pkg/go/build/syslist_test.go b/src/pkg/go/build/syslist_test.go
index 9157faf8cb94ff36308589456939b4ea4394ae41..3be2928f5253b8eeecd6eeb4807e156ce19b0f6b 100644 (file)
--- a/src/pkg/go/build/syslist_test.go
+++ b/src/pkg/go/build/syslist_test.go
@@ -55,7 +55,7 @@ var tests = []GoodFileTest{
 
 func TestGoodOSArch(t *testing.T) {
        for _, test := range tests {
-               if Default.goodOSArchFile(test.name) != test.result {
+               if Default.goodOSArchFile(test.name, make(map[string]bool)) != test.result {
                        t.Fatalf("goodOSArchFile(%q) != %v", test.name, test.result)
                }
        }