1 files changed, 117 insertions, 0 deletions
diff --git a/src/cmd/goinstall/path.go b/src/cmd/goinstall/path.go
new file mode 100644
index 000000000..1153e0471
--- /dev/null
+++ b/src/cmd/goinstall/path.go
@@ -0,0 +1,117 @@
+// Copyright 2011 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 (
+	"log"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+var (
+	gopath      []*pkgroot
+	imports     []string
+	defaultRoot *pkgroot // default root for remote packages
+)
+
+// set up gopath: parse and validate GOROOT and GOPATH variables
+func init() {
+	p, err := newPkgroot(root)
+	if err != nil {
+		log.Fatalf("Invalid GOROOT %q: %v", root, err)
+	}
+	p.goroot = true
+	gopath = []*pkgroot{p}
+
+	for _, p := range filepath.SplitList(os.Getenv("GOPATH")) {
+		if p == "" {
+			continue
+		}
+		r, err := newPkgroot(p)
+		if err != nil {
+			log.Printf("Invalid GOPATH %q: %v", p, err)
+			continue
+		}
+		gopath = append(gopath, r)
+		imports = append(imports, r.pkgDir())
+
+		// select first GOPATH entry as default
+		if defaultRoot == nil {
+			defaultRoot = r
+		}
+	}
+
+	// use GOROOT if no valid GOPATH specified
+	if defaultRoot == nil {
+		defaultRoot = gopath[0]
+	}
+}
+
+type pkgroot struct {
+	path   string
+	goroot bool // TODO(adg): remove this once Go tree re-organized
+}
+
+func newPkgroot(p string) (*pkgroot, os.Error) {
+	if !filepath.IsAbs(p) {
+		return nil, os.NewError("must be absolute")
+	}
+	ep, err := filepath.EvalSymlinks(p)
+	if err != nil {
+		return nil, err
+	}
+	return &pkgroot{path: ep}, nil
+}
+
+func (r *pkgroot) srcDir() string {
+	if r.goroot {
+		return filepath.Join(r.path, "src", "pkg")
+	}
+	return filepath.Join(r.path, "src")
+}
+
+func (r *pkgroot) pkgDir() string {
+	goos, goarch := runtime.GOOS, runtime.GOARCH
+	if e := os.Getenv("GOOS"); e != "" {
+		goos = e
+	}
+	if e := os.Getenv("GOARCH"); e != "" {
+		goarch = e
+	}
+	return filepath.Join(r.path, "pkg", goos+"_"+goarch)
+}
+
+func (r *pkgroot) binDir() string {
+	return filepath.Join(r.path, "bin")
+}
+
+func (r *pkgroot) hasSrcDir(name string) bool {
+	fi, err := os.Stat(filepath.Join(r.srcDir(), name))
+	if err != nil {
+		return false
+	}
+	return fi.IsDirectory()
+}
+
+func (r *pkgroot) hasPkg(name string) bool {
+	fi, err := os.Stat(filepath.Join(r.pkgDir(), name+".a"))
+	if err != nil {
+		return false
+	}
+	return fi.IsRegular()
+	// TODO(adg): check object version is consistent
+}
+
+// findPkgroot searches each of the gopath roots
+// for the source code for the given import path.
+func findPkgroot(importPath string) *pkgroot {
+	for _, r := range gopath {
+		if r.hasSrcDir(importPath) {
+			return r
+		}
+	}
+	return defaultRoot
+}