Make Directory.list pull-based, making it possible to pause, resume and cancel directory listing.

runtime/bin/directory.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_DIRECTORY_H_
 #define BIN_DIRECTORY_H_
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/native_service.h"
 #include "platform/globals.h"
 #include "platform/thread.h"
 
 
 namespace dart {
 namespace bin {
 
+enum ListType {
+  kListFile = 0,
+  kListDirectory = 1,
+  kListLink = 2,
+  kListError = 3,
+  kListDone = 4
+};
+
+class PathBuffer {
+ public:
+  PathBuffer();
+  ~PathBuffer() {
+    free(data_);
+  }
+
+  bool Add(const char* name);
+  bool AddW(const wchar_t* name);

[Søren Gjesse, 2013/06/13 11:59:20]

Please add implementations of AddW for all platforms with UNREACHABLE where it
is not used.

[Anders Johnsen, 2013/06/13 14:38:25]

Done.

+
+  char* AsString() const;
+  wchar_t* AsStringW() const;

[Søren Gjesse, 2013/06/13 11:59:20]

Ditto.

[Anders Johnsen, 2013/06/13 14:38:25]

Done.

+
+  void Reset(int new_length);
+
+  int length() const {
+    return length_;
+  }
+
+ private:
+  void* data_;
+  int length_;
+};
+
+class DirectoryListing;
+
+class DirectoryListingEntry {
+ public:
+  explicit DirectoryListingEntry(void* link)
+    : lister_(0), done_(false), link_(link) {}
+
+  ~DirectoryListingEntry() {
+    ResetLink();
+  }
+
+  ListType Next(DirectoryListing* listing);
+
+  DirectoryListingEntry* parent() const {
+    return parent_;
+  }
+
+  void set_parent(DirectoryListingEntry* parent) {
+    parent_ = parent;
+  }
+
+  void* link() {
+    return link_;
+  }
+
+  void set_link(void* link) {
+    link_ = link;
+  }
+
+  void ResetLink() {
+    if (link_ != NULL && (parent_ == NULL || parent_->link_ != link_)) {
+      free(link_);
+      link_ = NULL;
+    }
+    if (parent_ != NULL) {
+      link_ = parent_->link_;
+    }
+  }
+
+ private:
+  DirectoryListingEntry* parent_;
+  intptr_t lister_;
+  bool done_;
+  int path_length_;
+  void* link_;

[Søren Gjesse, 2013/06/13 11:59:20]

This void* member is really hard to understand. We should not have void* members
like this. You should define an abstract super class for this to type it. And
have different implementations for for different platforms.

Also the use of it needs some comments. When and how the linked list of file
system IDs is used.

[Anders Johnsen, 2013/06/13 14:38:25]

Done.

+};
+
 class DirectoryListing {
  public:
-  virtual ~DirectoryListing() {}
+  DirectoryListing(const char* dir_name, bool recursive, bool follow_links)
+    : top_(NULL),
+      error_(false),
+      recursive_(recursive),
+      follow_links_(follow_links) {
+    if (!path_buffer_.Add(dir_name)) {
+      error_ = true;
+    }
+    Push(new DirectoryListingEntry(NULL));
+  }
+
+  virtual ~DirectoryListing() {
+    while (!IsEmpty()) {
+      Pop();
+    }
+  }
+
   virtual bool HandleDirectory(char* dir_name) = 0;
   virtual bool HandleFile(char* file_name) = 0;
-  virtual bool HandleLink(char* file_name) = 0;
+  virtual bool HandleLink(char* link_name) = 0;
   virtual bool HandleError(const char* dir_name) = 0;
+  virtual void HandleDone() {}
+
+  void Push(DirectoryListingEntry* directory) {
+    directory->set_parent(top_);
+    top_ = directory;
+  }
+
+  void Pop() {
+    ASSERT(!IsEmpty());
+    DirectoryListingEntry* current = top_;
+    top_ = top_->parent();
+    delete current;
+  }
+
+  bool IsEmpty() const {
+    return top_ == NULL;
+  }
+
+  DirectoryListingEntry* top() const {
+    return top_;
+  }
+
+  bool recursive() const {
+    return recursive_;
+  }
+
+  bool follow_links() const {
+    return follow_links_;
+  }
+
+  char* CurrentPath() {
+    return path_buffer_.AsString();
+  }
+
+  PathBuffer& path_buffer() {
+    return path_buffer_;
+  }
+
+  bool error() const {
+    return error_;
+  }
+
+ private:
+  PathBuffer path_buffer_;
+  DirectoryListingEntry* top_;
+  bool error_;
+  bool recursive_;
+  bool follow_links_;
 };
 
 
 class AsyncDirectoryListing : public DirectoryListing {
  public:
   enum Response {
     kListFile = 0,
     kListDirectory = 1,
     kListLink = 2,
     kListError = 3,
     kListDone = 4
   };
 
-  explicit AsyncDirectoryListing(Dart_Port response_port)
-      : response_port_(response_port) {}
+  AsyncDirectoryListing(const char* dir_name,
+                        bool recursive,
+                        bool follow_links)
+      : DirectoryListing(dir_name, recursive, follow_links) {}
+
   virtual ~AsyncDirectoryListing() {}
   virtual bool HandleDirectory(char* dir_name);
   virtual bool HandleFile(char* file_name);
   virtual bool HandleLink(char* file_name);
   virtual bool HandleError(const char* dir_name);
+  virtual void HandleDone();
+
+  void SetArray(CObjectArray* array, intptr_t length) {
+    ASSERT(length % 2 == 0);
+    array_ = array;
+    index_ = 0;
+    length_ = length;
+  }
+
+  intptr_t index() const {
+    return index_;
+  }
 
  private:
-  CObjectArray* NewResponse(Response response, char* arg);
-  Dart_Port response_port_;
+  bool NewResponse(Response response, char* arg);
+  CObjectArray* array_;
+  intptr_t index_;
+  intptr_t length_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AsyncDirectoryListing);
 };
 
 
 class SyncDirectoryListing: public DirectoryListing {
  public:
-  explicit SyncDirectoryListing(Dart_Handle results)
-      : results_(results) {
+  SyncDirectoryListing(Dart_Handle results,
+                       const char* dir_name,
+                       bool recursive,
+                       bool follow_links)
+      : DirectoryListing(dir_name, recursive, follow_links),
+        results_(results) {
     add_string_ = DartUtils::NewString("add");
     directory_class_ =
         DartUtils::GetDartClass(DartUtils::kIOLibURL, "Directory");
     file_class_ =
         DartUtils::GetDartClass(DartUtils::kIOLibURL, "File");
     link_class_ =
         DartUtils::GetDartClass(DartUtils::kIOLibURL, "Link");
   }
   virtual ~SyncDirectoryListing() {}
   virtual bool HandleDirectory(char* dir_name);
@@ skipping 20 matching lines @@
     DOES_NOT_EXIST
   };
 
   // This enum must be kept in sync with the request values in
   // directory_impl.dart.
   enum DirectoryRequest {
     kCreateRequest = 0,
     kDeleteRequest = 1,
     kExistsRequest = 2,
     kCreateTempRequest = 3,
-    kListRequest = 4,
-    kRenameRequest = 5
+    kListStartRequest = 4,
+    kListNextRequest = 5,
+    kListStopRequest = 6,
+    kRenameRequest = 7
   };
 
-  static bool List(const char* path,
-                   bool recursive,
-                   bool follow_links,
-                   DirectoryListing* listing);
+  static void List(DirectoryListing* listing);
   static ExistsResult Exists(const char* path);
   static char* Current();
   static bool SetCurrent(const char* path);
   static bool Create(const char* path);
   static char* CreateTemp(const char* const_template);
   static bool Delete(const char* path, bool recursive);
   static bool Rename(const char* path, const char* new_path);
   static Dart_Port GetServicePort();
 
  private:
   static NativeService directory_service_;
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Directory);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_DIRECTORY_H_