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

runtime/bin/directory.cc

Index: runtime/bin/directory.cc
diff --git a/runtime/bin/directory.cc b/runtime/bin/directory.cc
index 6ca4ac0b4b6bd169989b3b6d19a57cd59a1ccb57..ace5b866a7bf69af51fae672a0bbb8d916d2fd3d 100644
--- a/runtime/bin/directory.cc
+++ b/runtime/bin/directory.cc
@@ -150,11 +150,11 @@ void FUNCTION_NAME(Directory_List)(Dart_NativeArguments args) {
                Dart_Null(),
                0,
                NULL);
-  SyncDirectoryListing sync_listing(results);
-  Directory::List(DartUtils::GetStringValue(path),
-                  DartUtils::GetBooleanValue(recursive),
-                  DartUtils::GetBooleanValue(follow_links),
-                  &sync_listing);
+  SyncDirectoryListing sync_listing(results,
+                                    DartUtils::GetStringValue(path),
+                                    DartUtils::GetBooleanValue(recursive),
+                                    DartUtils::GetBooleanValue(follow_links));
+  Directory::List(&sync_listing);
   Dart_SetReturnValue(args, results);
   Dart_ExitScope();
 }
@@ -221,25 +221,44 @@ static CObject* DirectoryCreateTempRequest(const CObjectArray& request) {
 }
 
 
-static CObject* DirectoryListRequest(const CObjectArray& request,
-                                     Dart_Port response_port) {
+static CObject* DirectoryListStartRequest(const CObjectArray& request) {
   if (request.Length() == 4 &&
       request[1]->IsString() &&
       request[2]->IsBool() &&
       request[3]->IsBool()) {
-    AsyncDirectoryListing* dir_listing =
-        new AsyncDirectoryListing(response_port);
     CObjectString path(request[1]);
     CObjectBool recursive(request[2]);
     CObjectBool follow_links(request[3]);
-    bool completed = Directory::List(
-        path.CString(), recursive.Value(), follow_links.Value(), dir_listing);
-    delete dir_listing;
-    CObjectArray* response = new CObjectArray(CObject::NewArray(2));
-    response->SetAt(
-        0,
-        new CObjectInt32(CObject::NewInt32(AsyncDirectoryListing::kListDone)));
-    response->SetAt(1, CObject::Bool(completed));
+    AsyncDirectoryListing* dir_listing =
+        new AsyncDirectoryListing(path.CString(),
+                                  recursive.Value(),
+                                  follow_links.Value());
+    return new CObjectIntptr(CObject::NewIntptr(
+        reinterpret_cast<intptr_t>(dir_listing)));
+  }
+  // Respond with an illegal argument list error message.
+  CObjectArray* response = new CObjectArray(CObject::NewArray(3));
+  response->SetAt(0, new CObjectInt32(
+      CObject::NewInt32(AsyncDirectoryListing::kListError)));
+  response->SetAt(1, CObject::Null());
+  response->SetAt(2, CObject::IllegalArgumentError());
+  return response;
+}
+
+
+static CObject* DirectoryListNextRequest(const CObjectArray& request) {
+  if (request.Length() == 2 &&
+      request[1]->IsIntptr()) {
+    CObjectIntptr ptr(request[1]);
+    AsyncDirectoryListing* dir_listing =
+        reinterpret_cast<AsyncDirectoryListing*>(ptr.Value());
+    const int kArraySize = 128;
+    CObjectArray* response = new CObjectArray(CObject::NewArray(kArraySize));
+    dir_listing->set_array(response, kArraySize);
+    Directory::List(dir_listing);

[Søren Gjesse, 2013/06/12 12:52:41]

You should just set the length of the response array instead of filling in
null's.

[Anders Johnsen, 2013/06/13 08:38:24]

Done.

+    for (intptr_t i = dir_listing->index(); i < kArraySize; i++) {
+      response->SetAt(i, CObject::Null());
+    }
     return response;
   }
   // Respond with an illegal argument list error message.
@@ -248,12 +267,24 @@ static CObject* DirectoryListRequest(const CObjectArray& request,
       CObject::NewInt32(AsyncDirectoryListing::kListError)));
   response->SetAt(1, CObject::Null());
   response->SetAt(2, CObject::IllegalArgumentError());
-  Dart_PostCObject(response_port, response->AsApiCObject());
+  return response;
+}
 
-  response = new CObjectArray(CObject::NewArray(2));
-  response->SetAt(
-      0, new CObjectInt32(CObject::NewInt32(AsyncDirectoryListing::kListDone)));
-  response->SetAt(1, CObject::False());
+
+static CObject* DirectoryListStopRequest(const CObjectArray& request) {
+  if (request.Length() == 2 && request[1]->IsIntptr()) {
+    CObjectIntptr ptr(request[1]);
+    AsyncDirectoryListing* dir_listing =
+        reinterpret_cast<AsyncDirectoryListing*>(ptr.Value());
+    delete dir_listing;
+    return new CObjectBool(CObject::Bool(true));
+  }
+  // Respond with an illegal argument list error message.
+  CObjectArray* response = new CObjectArray(CObject::NewArray(3));
+  response->SetAt(0, new CObjectInt32(
+      CObject::NewInt32(AsyncDirectoryListing::kListError)));
+  response->SetAt(1, CObject::Null());
+  response->SetAt(2, CObject::IllegalArgumentError());
   return response;
 }
 
@@ -294,8 +325,14 @@ static void DirectoryService(Dart_Port dest_port_id,
         case Directory::kCreateTempRequest:
           response = DirectoryCreateTempRequest(request);
           break;
-        case Directory::kListRequest:
-          response = DirectoryListRequest(request, reply_port_id);
+        case Directory::kListStartRequest:
+          response = DirectoryListStartRequest(request);
+          break;
+        case Directory::kListNextRequest:
+          response = DirectoryListNextRequest(request);
+          break;
+        case Directory::kListStopRequest:
+          response = DirectoryListStopRequest(request);
           break;
         case Directory::kRenameRequest:
           response = DirectoryRenameRequest(request, reply_port_id);
@@ -328,29 +365,35 @@ void FUNCTION_NAME(Directory_NewServicePort)(Dart_NativeArguments args) {
 }
 
 
-CObjectArray* AsyncDirectoryListing::NewResponse(Response type, char* arg) {
+bool AsyncDirectoryListing::NewResponse(Response type, char* arg) {

[Søren Gjesse, 2013/06/12 12:52:41]

This is no longer a single new response, but part off the response to next. How
about just using the response array for both type (even index) and name (odd
index) to avoid allocating all these two element arrays?

[Anders Johnsen, 2013/06/13 08:38:24]

Done.

   CObjectArray* response = new CObjectArray(CObject::NewArray(2));
   response->SetAt(0, new CObjectInt32(CObject::NewInt32(type)));
-  response->SetAt(1, new CObjectString(CObject::NewString(arg)));
-  return response;
+  if (arg != NULL) {
+    response->SetAt(1, new CObjectString(CObject::NewString(arg)));
+  } else {
+    response->SetAt(1, CObject::Null());
+  }
+  array_->SetAt(index_++, response);
+  return index_ < length_;
 }
 
 
 bool AsyncDirectoryListing::HandleDirectory(char* dir_name) {
-  CObjectArray* response = NewResponse(kListDirectory, dir_name);
-  return Dart_PostCObject(response_port_, response->AsApiCObject());
+  return NewResponse(kListDirectory, dir_name);
 }
 
 
 bool AsyncDirectoryListing::HandleFile(char* file_name) {
-  CObjectArray* response = NewResponse(kListFile, file_name);
-  return Dart_PostCObject(response_port_, response->AsApiCObject());
+  return NewResponse(kListFile, file_name);
 }
 
 
 bool AsyncDirectoryListing::HandleLink(char* link_name) {
-  CObjectArray* response = NewResponse(kListLink, link_name);
-  return Dart_PostCObject(response_port_, response->AsApiCObject());
+  return NewResponse(kListLink, link_name);
+}
+
+void AsyncDirectoryListing::HandleDone() {
+  NewResponse(kListDone, NULL);
 }
 
 
@@ -360,7 +403,8 @@ bool AsyncDirectoryListing::HandleError(const char* dir_name) {
   response->SetAt(0, new CObjectInt32(CObject::NewInt32(kListError)));
   response->SetAt(1, new CObjectString(CObject::NewString(dir_name)));
   response->SetAt(2, err);
-  return Dart_PostCObject(response_port_, response->AsApiCObject());
+  array_->SetAt(index_++, response);
+  return index_ < length_;
 }
 
 bool SyncDirectoryListing::HandleDirectory(char* dir_name) {