cmd/go: allow use of Context in 'go list -f'

Add a $Context variable to the template so that the build.Context values
such as BuildTags can be accessed.

Fixes #6666.

LGTM=adg, rsc
R=golang-codereviews, gobot, adg, rsc
CC=golang-codereviews
https://golang.org/cl/72770043

diff --git a/src/cmd/go/context.go b/src/cmd/go/context.go
new file mode 100644 (file)
index 0000000..68e5182
--- /dev/null
+++ b/src/cmd/go/context.go
@@ -0,0 +1,36 @@
+// Copyright 2014 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 main
+
+import (
+       "go/build"
+)
+
+type Context struct {
+       GOARCH        string   `json:",omitempty"` // target architecture
+       GOOS          string   `json:",omitempty"` // target operating system
+       GOROOT        string   `json:",omitempty"` // Go root
+       GOPATH        string   `json:",omitempty"` // Go path
+       CgoEnabled    bool     `json:",omitempty"` // whether cgo can be used
+       UseAllFiles   bool     `json:",omitempty"` // use files regardless of +build lines, file names
+       Compiler      string   `json:",omitempty"` // compiler to assume when computing target paths
+       BuildTags     []string `json:",omitempty"` // build constraints to match in +build lines
+       ReleaseTags   []string `json:",omitempty"` // releases the current release is compatible with
+       InstallSuffix string   `json:",omitempty"` // suffix to use in the name of the install dir
+}
+
+func newContext(c *build.Context) *Context {
+       return &Context{
+               GOARCH:        c.GOARCH,
+               GOOS:          c.GOOS,
+               GOROOT:        c.GOROOT,
+               CgoEnabled:    c.CgoEnabled,
+               UseAllFiles:   c.UseAllFiles,
+               Compiler:      c.Compiler,
+               BuildTags:     c.BuildTags,
+               ReleaseTags:   c.ReleaseTags,
+               InstallSuffix: c.InstallSuffix,
+       }
+}

diff --git a/src/cmd/go/doc.go b/src/cmd/go/doc.go
index d5f1d1bf24f1d69db7e7a4179fdd7f13b63907e9..664bc83bdecdfcd20956060db3178296a7dff0bd 100644 (file)
--- a/src/cmd/go/doc.go
+++ b/src/cmd/go/doc.go
@@ -283,8 +283,7 @@ The default output shows the package import path:
 
 The -f flag specifies an alternate format for the list, using the
 syntax of package template.  The default output is equivalent to -f
-'{{.ImportPath}}'.  One extra template function is available, "join",
-which calls strings.Join. The struct being passed to the template is:
+'{{.ImportPath}}'. The struct being passed to the template is:
 
     type Package struct {
         Dir        string // directory containing package sources
@@ -332,6 +331,26 @@ which calls strings.Join. The struct being passed to the template is:
         XTestImports []string // imports from XTestGoFiles
     }
 
+The template function "join" calls strings.Join.
+
+The template function "context" returns the build context, defined as:
+
+       type Context struct {
+               GOARCH        string   // target architecture
+               GOOS          string   // target operating system
+               GOROOT        string   // Go root
+               GOPATH        string   // Go path
+               CgoEnabled    bool     // whether cgo can be used
+               UseAllFiles   bool     // use files regardless of +build lines, file names
+               Compiler      string   // compiler to assume when computing target paths
+               BuildTags     []string // build constraints to match in +build lines
+               ReleaseTags   []string // releases the current release is compatible with
+               InstallSuffix string   // suffix to use in the name of the install dir
+       }
+
+For more information about the meaning of these fields see the documentation
+for the go/build package's Context type.
+
 The -json flag causes the package data to be printed in JSON format
 instead of using the template format.
 

diff --git a/src/cmd/go/list.go b/src/cmd/go/list.go
index 2cd8e5fa78b4b9b7f35e7eba59d56ced3b4b389a..e2b0ba0dc102fa4a58c52869b1dbb0393133a7b9 100644 (file)
--- a/src/cmd/go/list.go
+++ b/src/cmd/go/list.go
@@ -27,8 +27,7 @@ The default output shows the package import path:
 
 The -f flag specifies an alternate format for the list, using the
 syntax of package template.  The default output is equivalent to -f
-'{{.ImportPath}}'.  One extra template function is available, "join",
-which calls strings.Join. The struct being passed to the template is:
+'{{.ImportPath}}'. The struct being passed to the template is:
 
     type Package struct {
         Dir        string // directory containing package sources
@@ -76,6 +75,26 @@ which calls strings.Join. The struct being passed to the template is:
         XTestImports []string // imports from XTestGoFiles
     }
 
+The template function "join" calls strings.Join.
+
+The template function "context" returns the build context, defined as:
+
+       type Context struct {
+               GOARCH        string   // target architecture
+               GOOS          string   // target operating system
+               GOROOT        string   // Go root
+               GOPATH        string   // Go path
+               CgoEnabled    bool     // whether cgo can be used
+               UseAllFiles   bool     // use files regardless of +build lines, file names
+               Compiler      string   // compiler to assume when computing target paths
+               BuildTags     []string // build constraints to match in +build lines
+               ReleaseTags   []string // releases the current release is compatible with
+               InstallSuffix string   // suffix to use in the name of the install dir
+       }
+
+For more information about the meaning of these fields see the documentation
+for the go/build package's Context type.
+
 The -json flag causes the package data to be printed in JSON format
 instead of using the template format.
 
@@ -131,7 +150,18 @@ func runList(cmd *Command, args []string) {
                        out.Write(nl)
                }
        } else {
-               tmpl, err := template.New("main").Funcs(template.FuncMap{"join": strings.Join}).Parse(*listFmt)
+               var cachedCtxt *Context
+               context := func() *Context {
+                       if cachedCtxt == nil {
+                               cachedCtxt = newContext(&buildContext)
+                       }
+                       return cachedCtxt
+               }
+               fm := template.FuncMap{
+                       "join":    strings.Join,
+                       "context": context,
+               }
+               tmpl, err := template.New("main").Funcs(fm).Parse(*listFmt)
                if err != nil {
                        fatalf("%s", err)
                }

diff --git a/src/cmd/go/test.bash b/src/cmd/go/test.bash
index 1091695b3744e8c2ed51f770c7e2e3eb1f2768da..45215de4ded9ce2f197087c5c603b63a568f874e 100755 (executable)
--- a/src/cmd/go/test.bash
+++ b/src/cmd/go/test.bash
@@ -694,6 +694,12 @@ unset go_cmds
 unset ldflags
 unset GOPATH
 
+TEST list template can use context function
+if ! ./testgo list -f "GOARCH: {{context.GOARCH}}"; then 
+       echo unable to use context in list template
+       ok=false
+fi
+
 # clean up
 if $started; then stop; fi
 rm -rf testdata/bin testdata/bin1