Reuse blacklisting code in exp_archive.

client/cmd/isolate/exp_archive.go

Index: client/cmd/isolate/exp_archive.go
diff --git a/client/cmd/isolate/exp_archive.go b/client/cmd/isolate/exp_archive.go
index a65bccaf5f1d7afade8d43c0d3a17ffc4f2cbbb6..c561f247036b5e4199b7d4a3ee821daf66e4bc06 100644
--- a/client/cmd/isolate/exp_archive.go
+++ b/client/cmd/isolate/exp_archive.go
@@ -30,6 +30,7 @@ import (
 	"github.com/maruel/subcommands"
 	"golang.org/x/net/context"
 
+	"github.com/luci/luci-go/client/internal/common"
 	"github.com/luci/luci-go/client/isolate"
 	"github.com/luci/luci-go/common/auth"
 	logpb "github.com/luci/luci-go/common/eventlog/proto"
@@ -100,8 +101,8 @@ func (ig *itemGroup) AddItem(item *Item) {
 
 // partitioningWalker contains the state necessary to partition isolate deps by handling multiple os.WalkFunc invocations.
 type partitioningWalker struct {
-	// rootDir must be initialized before walkFn is called.
-	rootDir string
+	// fsView must be initialized before walkFn is called.
+	fsView common.FilesystemView
 
 	parts partitionedDeps
 }
@@ -119,15 +120,20 @@ func (pw *partitioningWalker) walkFn(path string, info os.FileInfo, err error) e
 	if err != nil {
 		return err
 	}
-	if info.IsDir() {
-		return nil
-	}
 
-	relPath, err := filepath.Rel(pw.rootDir, path)
+	relPath, err := pw.fsView.RelativePath(path)
 	if err != nil {
 		return err
 	}
 
+	if relPath == "" { // empty string indicates skip.
+		return returnSkip(info)
+	}
+
+	if info.IsDir() {
+		return nil
+	}
+
 	item := &Item{
 		Path:    path,
 		RelPath: relPath,
@@ -146,9 +152,24 @@ func (pw *partitioningWalker) walkFn(path string, info os.FileInfo, err error) e
 	return nil
 }
 
+// returnSkip returns the return value expected from a filepath.WalkFunc in the case where no more processing of file should occur.

[mithro, 2017/07/21 04:58:51]

nit: This sentence is a bit clunky.

[mcgreevy, 2017/07/21 05:40:38]

I've reworded; it's quite hard to word simply, though. Any suggestions are
welcome.

I've also moved this into a common package, since it was duplicated in
directory.go.

+func returnSkip(file os.FileInfo) error {
+	if file.IsDir() {
+		// Must not return io.SkipDir for file, filepath.walk() handles this badly.

[mithro, 2017/07/21 04:58:51]

Could you add a reference to info about this? Maybe a bug or godoc link?

[mcgreevy, 2017/07/21 05:40:38]

Done.

+		return filepath.SkipDir
+	}
+	return nil
+}
+
 // partitionDeps walks each of the deps, partioning the results into symlinks and files categorized by size.
 func partitionDeps(deps []string, rootDir string) (partitionedDeps, error) {
-	walker := partitioningWalker{rootDir: rootDir}
+	// TODO(mcgreevy): initialize FilesystemView with blacklist.
+	fsView, err := common.NewFilesystemView(rootDir, nil)
+	if err != nil {
+		return partitionedDeps{}, err
+	}
+
+	walker := partitioningWalker{fsView: fsView}
 	for _, dep := range deps {
 		// Try to walk dep. If dep is a file (or symlink), the inner function is called exactly once.
 		if err := filepath.Walk(filepath.Clean(dep), walker.walkFn); err != nil {