Add support for compression filters in the mojo dart:io

mojo/dart/embedder/mojo_io_natives.cc

Index: mojo/dart/embedder/mojo_io_natives.cc
diff --git a/mojo/dart/embedder/mojo_io_natives.cc b/mojo/dart/embedder/mojo_io_natives.cc
index dd18a868e661935a18429c4b1a3c8e9d8d4e16d3..80f283a8875aed4052cdeec5005325151195215c 100644
--- a/mojo/dart/embedder/mojo_io_natives.cc
+++ b/mojo/dart/embedder/mojo_io_natives.cc
@@ -4,10 +4,12 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <limits>
 
 #include "dart/runtime/include/dart_api.h"
 #include "mojo/dart/embedder/builtin.h"
 #include "mojo/dart/embedder/common.h"
+#include "mojo/dart/embedder/io/filter.h"
 #include "mojo/dart/embedder/io/internet_address.h"
 #include "mojo/dart/embedder/mojo_dart_state.h"
 #include "mojo/public/cpp/system/macros.h"
@@ -16,6 +18,11 @@ namespace mojo {
 namespace dart {
 
 #define MOJO_IO_NATIVE_LIST(V)                                                 \
+  V(Filter_CreateZLibDeflate, 8)                                               \
+  V(Filter_CreateZLibInflate, 4)                                               \
+  V(Filter_End, 1)                                                             \
+  V(Filter_Process, 4)                                                         \
+  V(Filter_Processed, 3)                                                       \
   V(InternetAddress_Parse, 1)                                                  \
   V(InternetAddress_Reverse, 1)                                                \
   V(Platform_NumberOfProcessors, 0)                                            \
@@ -68,6 +75,266 @@ const uint8_t* MojoIoNativeSymbol(Dart_NativeFunction nf) {
   return nullptr;
 }
 
+class IOBuffer {
+ public:
+  static Dart_Handle Allocate(intptr_t size, uint8_t **buffer) {
+    uint8_t* data = Allocate(size);
+    Dart_Handle result = Dart_NewExternalTypedData(
+        Dart_TypedData_kUint8, data, size);
+    Dart_NewWeakPersistentHandle(result, data, size, IOBuffer::Finalizer);
+
+    if (Dart_IsError(result)) {
+      Free(data);
+      Dart_PropagateError(result);
+    }
+    if (buffer != NULL) {
+      *buffer = data;
+    }
+    return result;
+  }
+
+  // Allocate IO buffer storage.
+  static uint8_t* Allocate(intptr_t size) {
+    return new uint8_t[size];
+  }
+
+  // Function for disposing of IO buffer storage. All backing storage
+  // for IO buffers must be freed using this function.
+  static void Free(void* buffer) {
+    delete[] reinterpret_cast<uint8_t*>(buffer);
+  }
+
+  // Function for finalizing external byte arrays used as IO buffers.
+  static void Finalizer(void* isolate_callback_data,
+                        Dart_WeakPersistentHandle handle,
+                        void* buffer) {
+    Free(buffer);
+  }
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(IOBuffer);
+};
+
+static Filter* GetFilter(Dart_Handle filter_obj) {
+  Filter* filter;
+  Dart_Handle result = Filter::GetFilterPointerNativeField(filter_obj, &filter);
+  if (Dart_IsError(result)) {
+    Dart_PropagateError(result);
+  }
+  if (filter == NULL) {
+    Dart_ThrowException(DartEmbedder::NewInternalError("Filter destroyed"));
+  }
+  return filter;
+}
+
+static void EndFilter(Dart_Handle filter_obj, Filter* filter) {

[zra, 2016/03/02 23:30:40]

This method of deleting the filter relies on the Dart library code calling
_FilterImpl.end(), otherwise the filter will leak. This should really be deleted
in the finalizer for a weak persistent handle set up by
SetFilterPointerNativeField(), but for now, I guess we should probably just use
the same code as upstream.

[Cutch, 2016/03/03 15:46:56]

Acknowledged.

+  Filter::SetFilterPointerNativeField(filter_obj, NULL);
+  delete filter;
+}
+
+static uint8_t* copyDictionary(Dart_Handle dictionary_obj) {
+  uint8_t* src = NULL;
+  intptr_t size;
+  Dart_TypedData_Type type;
+
+  if (Dart_IsError(Dart_ListLength(dictionary_obj, &size))) {
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to get the zlib dictionary length"));
+  }
+
+  uint8_t* dictionary = new uint8_t[size];
+
+  if (dictionary == NULL) {
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to allocate buffer for the zlib dictionary"));
+  }
+
+  Dart_Handle result = Dart_TypedDataAcquireData(
+      dictionary_obj, &type, reinterpret_cast<void**>(&src), &size);
+  if (!Dart_IsError(result)) {
+    memmove(dictionary, src, size);
+    Dart_TypedDataReleaseData(dictionary_obj);
+  } else {
+    if (Dart_IsError(Dart_ListGetAsBytes(dictionary_obj, 0, dictionary,
+                                         size))) {
+      Dart_ThrowException(DartEmbedder::NewInternalError(
+          "Failed to get the zlib dictionary"));
+    }
+  }
+
+  return dictionary;
+}
+
+void Filter_CreateZLibInflate(Dart_NativeArguments args) {
+  Dart_Handle filter_obj = Dart_GetNativeArgument(args, 0);
+  Dart_Handle window_bits_obj = Dart_GetNativeArgument(args, 1);
+  int64_t window_bits = DartEmbedder::GetIntegerValue(window_bits_obj);
+  Dart_Handle dict_obj = Dart_GetNativeArgument(args, 2);
+  uint8_t* dictionary = NULL;
+  intptr_t dictionary_length = 0;
+  if (!Dart_IsNull(dict_obj)) {
+    dictionary = copyDictionary(dict_obj);
+    if (dictionary != NULL) {
+      dictionary_length = 0;
+      Dart_ListLength(dict_obj, &dictionary_length);
+    }
+  }
+  Dart_Handle raw_obj = Dart_GetNativeArgument(args, 3);
+  bool raw;
+  if (Dart_IsError(Dart_BooleanValue(raw_obj, &raw))) {
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to get 'raw' parameter"));
+  }
+  Filter* filter = new ZLibInflateFilter(static_cast<int32_t>(window_bits),
+                                         dictionary, dictionary_length, raw);
+  if (!filter->Init()) {
+    delete filter;
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to create ZLibInflateFilter"));
+  }
+  Dart_Handle result = Filter::SetFilterPointerNativeField(filter_obj, filter);
+  if (Dart_IsError(result)) {
+    delete filter;
+    Dart_PropagateError(result);
+  }
+}
+
+void Filter_CreateZLibDeflate(Dart_NativeArguments args) {
+  Dart_Handle filter_obj = Dart_GetNativeArgument(args, 0);
+  Dart_Handle gzip_obj = Dart_GetNativeArgument(args, 1);
+  bool gzip = DartEmbedder::GetBooleanValue(gzip_obj);
+  Dart_Handle level_obj = Dart_GetNativeArgument(args, 2);
+  int64_t level = DartEmbedder::GetInt64ValueCheckRange(
+      level_obj,
+      std::numeric_limits<int32_t>::min(),
+      std::numeric_limits<int32_t>::max());
+  Dart_Handle window_bits_obj = Dart_GetNativeArgument(args, 3);
+  int64_t window_bits = DartEmbedder::GetIntegerValue(window_bits_obj);
+  Dart_Handle mLevel_obj = Dart_GetNativeArgument(args, 4);
+  int64_t mem_level = DartEmbedder::GetIntegerValue(mLevel_obj);
+  Dart_Handle strategy_obj = Dart_GetNativeArgument(args, 5);
+  int64_t strategy = DartEmbedder::GetIntegerValue(strategy_obj);
+  Dart_Handle dict_obj = Dart_GetNativeArgument(args, 6);
+  uint8_t* dictionary = NULL;
+  intptr_t dictionary_length = 0;
+  if (!Dart_IsNull(dict_obj)) {
+    dictionary = copyDictionary(dict_obj);
+    if (dictionary != NULL) {
+      dictionary_length = 0;
+      Dart_ListLength(dict_obj, &dictionary_length);
+    }
+  }
+  Dart_Handle raw_obj = Dart_GetNativeArgument(args, 7);
+  bool raw = DartEmbedder::GetBooleanValue(raw_obj);
+  Filter* filter = new ZLibDeflateFilter(gzip, static_cast<int32_t>(level),
+                                         static_cast<int32_t>(window_bits),
+                                         static_cast<int32_t>(mem_level),
+                                         static_cast<int32_t>(strategy),
+                                         dictionary, dictionary_length, raw);
+  if (!filter->Init()) {
+    delete filter;
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to create ZLibDeflateFilter"));
+  }
+  Dart_Handle result = Filter::SetFilterPointerNativeField(filter_obj, filter);
+  if (Dart_IsError(result)) {
+    delete filter;
+    Dart_PropagateError(result);
+  }
+}
+
+void Filter_Process(Dart_NativeArguments args) {
+  Dart_Handle filter_obj = Dart_GetNativeArgument(args, 0);
+  Filter* filter = GetFilter(filter_obj);
+  Dart_Handle data_obj = Dart_GetNativeArgument(args, 1);
+  intptr_t start =
+      DartEmbedder::GetIntptrValue(Dart_GetNativeArgument(args, 2));
+  intptr_t end = DartEmbedder::GetIntptrValue(Dart_GetNativeArgument(args, 3));
+  intptr_t chunk_length = end - start;
+  intptr_t length;
+  Dart_TypedData_Type type;
+  uint8_t* buffer = NULL;
+  Dart_Handle result = Dart_TypedDataAcquireData(
+      data_obj, &type, reinterpret_cast<void**>(&buffer), &length);
+
+  if (!Dart_IsError(result)) {
+    DCHECK(type == Dart_TypedData_kUint8 || type == Dart_TypedData_kInt8);
+    if (type != Dart_TypedData_kUint8 && type != Dart_TypedData_kInt8) {
+      Dart_TypedDataReleaseData(data_obj);
+      Dart_ThrowException(DartEmbedder::NewInternalError(
+          "Invalid argument passed to Filter_Process"));
+    }
+    uint8_t* zlib_buffer = new uint8_t[chunk_length];
+    if (zlib_buffer == NULL) {
+      Dart_TypedDataReleaseData(data_obj);
+      Dart_ThrowException(DartEmbedder::NewInternalError(
+          "Failed to allocate buffer for zlib"));
+    }
+    memmove(zlib_buffer, buffer + start, chunk_length);
+    Dart_TypedDataReleaseData(data_obj);
+    buffer = zlib_buffer;
+  } else {
+    if (Dart_IsError(Dart_ListLength(data_obj, &length))) {
+      Dart_ThrowException(DartEmbedder::NewInternalError(
+          "Failed to get list length"));
+    }
+    buffer = new uint8_t[chunk_length];
+    if (Dart_IsError(Dart_ListGetAsBytes(
+            data_obj, start, buffer, chunk_length))) {
+      delete[] buffer;
+      Dart_ThrowException(DartEmbedder::NewInternalError(
+          "Failed to get list bytes"));
+    }
+  }
+  // Process will take ownership of buffer, if successful.
+  if (!filter->Process(buffer, chunk_length)) {
+    delete[] buffer;
+    EndFilter(filter_obj, filter);
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Call to Process while still processing data"));
+  }
+}
+
+void Filter_Processed(Dart_NativeArguments args) {
+  Dart_Handle filter_obj = Dart_GetNativeArgument(args, 0);
+  Filter* filter = GetFilter(filter_obj);
+  Dart_Handle flush_obj = Dart_GetNativeArgument(args, 1);
+  bool flush;
+  if (Dart_IsError(Dart_BooleanValue(flush_obj, &flush))) {
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to get 'flush' parameter"));
+  }
+  Dart_Handle end_obj = Dart_GetNativeArgument(args, 2);
+  bool end;
+  if (Dart_IsError(Dart_BooleanValue(end_obj, &end))) {
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Failed to get 'end' parameter"));
+  }
+  intptr_t read = filter->Processed(filter->processed_buffer(),
+                                    filter->processed_buffer_size(),
+                                    flush,
+                                    end);
+  if (read < 0) {
+    // Error, end filter.
+    EndFilter(filter_obj, filter);
+    Dart_ThrowException(DartEmbedder::NewInternalError(
+        "Filter error, bad data"));
+  } else if (read == 0) {
+    Dart_SetReturnValue(args, Dart_Null());
+  } else {
+    uint8_t* io_buffer;
+    Dart_Handle result = IOBuffer::Allocate(read, &io_buffer);
+    memmove(io_buffer, filter->processed_buffer(), read);
+    Dart_SetReturnValue(args, result);
+  }
+}
+
+void Filter_End(Dart_NativeArguments args) {
+  Dart_Handle filter_obj = Dart_GetNativeArgument(args, 0);
+  Filter* filter = GetFilter(filter_obj);
+  EndFilter(filter_obj, filter);
+}
+
 void InternetAddress_Parse(Dart_NativeArguments arguments) {
   const char* address = DartEmbedder::GetStringArgument(arguments, 0);
   CHECK(address != nullptr);