Merge pull request #8 from erizocosmico/fix/gopath

implement GoPath helper and prepare for multiple go paths

.travis.yml

@@ -8,6 +8,9 @@ matrix:
     allow_failures:
         - go: tip
 
+env:
+  - GOPATH=/tmp/whatever:$GOPATH
+
 install:
   - rm -rf $GOPATH/src/gopkg.in/src-d
   - mkdir -p $GOPATH/src/gopkg.in/src-d

ast.go

@@ -5,7 +5,6 @@ import (
 	"go/ast"
 	"go/parser"
 	"go/token"
-	"path/filepath"
 	"strings"
 )
 
@@ -33,7 +32,12 @@ type packageFilter func(string, *ast.Package) bool
 // one left.
 func parseAndFilterPackages(path string, filter packageFilter) (pkg *ast.Package, err error) {
 	fset := token.NewFileSet()
-	pkgs, err := parser.ParseDir(fset, filepath.Join(goSrc, path), nil, parser.ParseComments)
+	srcDir, err := DefaultGoPath.Abs(path)
+	if err != nil {
+		return nil, err
+	}
+
+	pkgs, err := parser.ParseDir(fset, srcDir, nil, parser.ParseComments)
 	if err != nil {
 		return nil, err
 	}

importer.go

@@ -14,10 +14,39 @@ import (
 	"sync"
 )
 
-var (
-	goPath = os.Getenv("GOPATH")
-	goSrc  = filepath.Join(goPath, "src")
-)
+// ErrNotInGoPath is an error returned when a package is not in any of the
+// possible go paths.
+var ErrNotInGoPath = fmt.Errorf("parseutil: package is not in any of the go paths")
+
+// GoPath is the collection of all go paths.
+type GoPath []string
+
+// Abs returns the absolute path to a package. The go path in the absolute path
+// that will be returned is the first that contains the given package.
+func (gp GoPath) Abs(pkg string) (string, error) {
+	path, err := gp.PathOf(pkg)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(path, "src", pkg), nil
+}
+
+// PathOf returns the first go path that contains the given package.
+func (gp GoPath) PathOf(pkg string) (string, error) {
+	for _, p := range gp {
+		if _, err := os.Stat(filepath.Join(p, "src", pkg)); err == nil {
+			return p, nil
+		} else if !os.IsNotExist(err) {
+			return "", err
+		}
+	}
+	return "", ErrNotInGoPath
+}
+
+// DefaultGoPath contains the default list of go paths provided either via
+// GOPATH environment variable or the default value.
+var DefaultGoPath = GoPath(filepath.SplitList(build.Default.GOPATH))
 
 // FileFilter returns true if the given file needs to be kept.
 type FileFilter func(pkgPath, file string, typ FileType) bool
@@ -86,7 +115,7 @@ func (i *Importer) Import(path string) (*types.Package, error) {
 // ImportWithFilters works like Import but filtering the source files to parse using
 // the passed FileFilters.
 func (i *Importer) ImportWithFilters(path string, filters FileFilters) (*types.Package, error) {
-	return i.ImportFromWithFilters(path, goSrc, 0, filters)
+	return i.ImportFromWithFilters(path, "", 0, filters)
 }
 
 // ImportFrom returns the imported package for the given import
@@ -115,7 +144,15 @@ func (i *Importer) ImportFromWithFilters(path, srcDir string, mode types.ImportM
 	}
 
 	// If it's not on the GOPATH use the default importer instead
-	if !strings.HasPrefix(root, goPath) {
+	useDefaultImporter := true
+	for _, p := range DefaultGoPath {
+		if strings.HasPrefix(root, p) {
+			useDefaultImporter = false
+			break
+		}
+	}
+
+	if useDefaultImporter {
 		i.mut.Lock()
 		defer i.mut.Unlock()
 

importer_test.go

@@ -1,7 +1,6 @@
 package parseutil_test
 
 import (
-	"os"
 	"path/filepath"
 	"testing"
 
@@ -13,20 +12,24 @@ import (
 
 const project = "gopkg.in/src-d/go-parse-utils.v1"
 
-var (
-	goPath = os.Getenv("GOPATH")
-	goSrc  = filepath.Join(goPath, "src")
-)
-
-var projectPath = filepath.Join(goSrc, project)
+var projectPath = func() string {
+	path, err := parseutil.DefaultGoPath.Abs(project)
+	if err != nil {
+		panic(err)
+	}
+	return path
+}()
 
 func projectFile(path string) string {
 	return filepath.Join(projectPath, path)
 }
 
 func TestGetSourceFiles(t *testing.T) {
-	_, paths, err := parseutil.NewImporter().GetSourceFiles(project, goPath, parseutil.FileFilters{})
-	require.Nil(t, err)
+	projPath, err := parseutil.DefaultGoPath.PathOf(project)
+	require.NoError(t, err)
+	_, paths, err := parseutil.NewImporter().
+		GetSourceFiles(project, projPath, parseutil.FileFilters{})
+	require.NoError(t, err)
 	expected := []string{
 		projectFile("ast.go"),
 		projectFile("importer.go"),
@@ -72,7 +75,7 @@ func TestImportGoogleGrpc(t *testing.T) {
 
 func TestImportFrom(t *testing.T) {
 	imp := parseutil.NewImporter()
-	pkg, err := imp.ImportFrom(project, goSrc, 0)
+	pkg, err := imp.ImportFrom(project, "", 0)
 	require.Nil(t, err)
 	require.Equal(t, "parseutil", pkg.Name())
 }