godoc: better handling of deep directory trees

also: fix a logic error with filter use at startup

R=rsc
CC=golang-dev
https://golang.org/cl/2184044

src/cmd/godoc/dirtrees.go

@@ -171,24 +171,24 @@ func (b *treeBuilder) newDirTree(path, name string, depth int) *Directory {
 }
 
 
-// Maximum directory depth, adjust as needed.
-const maxDirDepth = 24
-
 // newDirectory creates a new package directory tree with at most maxDepth
 // levels, anchored at root. The result tree is pruned such that it only
 // contains directories that contain package files or that contain
 // subdirectories containing package files (transitively). If a non-nil
 // pathFilter is provided, directory paths additionally must be accepted
-// by the filter (i.e., pathFilter(path) must be true). If maxDepth is
+// by the filter (i.e., pathFilter(path) must be true). If a value >= 0 is
-// too shallow, the leaf nodes are assumed to contain package files even if
+// provided for maxDepth, nodes at larger depths are pruned as well; they
-// their contents are not known (i.e., in this case the tree may contain
+// are assumed to contain package files even if their contents are not known
-// directories w/o any package files).
+// (i.e., in this case the tree may contain directories w/o any package files).
 //
 func newDirectory(root string, pathFilter func(string) bool, maxDepth int) *Directory {
 	d, err := os.Lstat(root)
 	if err != nil || !isPkgDir(d) {
 		return nil
 	}
+	if maxDepth < 0 {
+		maxDepth = 1e6 // "infinity"
+	}
 	b := treeBuilder{pathFilter, maxDepth}
 	return b.newDirTree(root, d.Name, 0)
 }

src/cmd/godoc/godoc.go

@@ -155,7 +155,7 @@ func updateFilterFile() {
 	// for each user-defined file system mapping, compute
 	// respective directory tree w/o filter for accuracy
 	fsMap.Iterate(func(path string, value *RWValue) bool {
-		value.set(newDirectory(path, nil, maxDirDepth))
+		value.set(newDirectory(path, nil, -1))
 		return true
 	})
 
@@ -194,7 +194,7 @@ func initDirTrees() {
 	// for each user-defined file system mapping, compute
 	// respective directory tree quickly using pathFilter
 	go fsMap.Iterate(func(path string, value *RWValue) bool {
-		value.set(newDirectory(path, getPathFilter(), maxDirDepth))
+		value.set(newDirectory(path, getPathFilter(), -1))
 		return true
 	})
 
@@ -1203,10 +1203,11 @@ func (h *httpHandler) getPageInfo(abspath, relpath, pkgname string, mode PageInf
 		}
 	}
 	if dir == nil {
-		// no directory tree present (either early after startup
+		// no directory tree present (too early after startup or
-		// or command-line mode, or we don't have a tree for the
+		// command-line mode); compute one level for this page
-		// directory yet; e.g. google3); compute one level for this page
+		// note: cannot use path filter here because in general
-		dir = newDirectory(abspath, getPathFilter(), 1)
+		//       it doesn't contain the fsTree path
+		dir = newDirectory(abspath, nil, 1)
 	}
 
 	return PageInfo{abspath, plist, past, pdoc, dir.listing(true), h.isPkg, nil}

src/cmd/godoc/main.go

@@ -127,7 +127,7 @@ func dosync(c *http.Conn, r *http.Request) {
 		// TODO(gri): The directory tree may be temporarily out-of-sync.
 		//            Consider keeping separate time stamps so the web-
 		//            page can indicate this discrepancy.
-		fsTree.set(newDirectory(*goroot, nil, maxDirDepth))
+		fsTree.set(newDirectory(*goroot, nil, -1))
 		fallthrough
 	case 1:
 		// sync failed because no files changed;
@@ -259,7 +259,7 @@ func main() {
 		// 1) set timestamp right away so that the indexer is kicked on
 		fsTree.set(nil)
 		// 2) compute initial directory tree in a goroutine so that launch is quick
-		go func() { fsTree.set(newDirectory(*goroot, nil, maxDirDepth)) }()
+		go func() { fsTree.set(newDirectory(*goroot, nil, -1)) }()
 
 		// Initialize directory trees for user-defined file systems (-path flag).
 		initDirTrees()