1 files changed, 259 insertions, 0 deletions
diff --git a/dom/base/CompressionStream.cpp b/dom/base/CompressionStream.cpp
new file mode 100644
index 0000000000..65413b851b
--- /dev/null
+++ b/dom/base/CompressionStream.cpp
@@ -0,0 +1,259 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/CompressionStream.h"
+
+#include "js/TypeDecls.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/dom/CompressionStreamBinding.h"
+#include "mozilla/dom/ReadableStream.h"
+#include "mozilla/dom/WritableStream.h"
+#include "mozilla/dom/TransformStream.h"
+#include "mozilla/dom/TextDecoderStream.h"
+#include "mozilla/dom/TransformerCallbackHelpers.h"
+#include "mozilla/dom/UnionTypes.h"
+
+#include "ZLibHelper.h"
+
+// See the zlib manual in https://www.zlib.net/manual.html or in
+// https://searchfox.org/mozilla-central/source/modules/zlib/src/zlib.h
+
+namespace mozilla::dom {
+
+class CompressionStreamAlgorithms : public TransformerAlgorithmsWrapper {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CompressionStreamAlgorithms,
+                                           TransformerAlgorithmsBase)
+
+  explicit CompressionStreamAlgorithms(CompressionFormat format) {
+    int8_t err = deflateInit2(&mZStream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+                              ZLibWindowBits(format), 8 /* default memLevel */,
+                              Z_DEFAULT_STRATEGY);
+    if (err == Z_MEM_ERROR) {
+      MOZ_CRASH("Out of memory");
+    }
+    MOZ_ASSERT(err == Z_OK);
+  }
+
+  // Step 3 of
+  // https://wicg.github.io/compression/#dom-compressionstream-compressionstream
+  // Let transformAlgorithm be an algorithm which takes a chunk argument and
+  // runs the compress and enqueue a chunk algorithm with this and chunk.
+  MOZ_CAN_RUN_SCRIPT
+  void TransformCallbackImpl(JS::Handle<JS::Value> aChunk,
+                             TransformStreamDefaultController& aController,
+                             ErrorResult& aRv) override {
+    AutoJSAPI jsapi;
+    if (!jsapi.Init(aController.GetParentObject())) {
+      aRv.ThrowUnknownError("Internal error");
+      return;
+    }
+    JSContext* cx = jsapi.cx();
+
+    // https://wicg.github.io/compression/#compress-and-enqueue-a-chunk
+
+    // Step 1: If chunk is not a BufferSource type, then throw a TypeError.
+    RootedUnion<OwningArrayBufferViewOrArrayBuffer> bufferSource(cx);
+    if (!bufferSource.Init(cx, aChunk)) {
+      aRv.MightThrowJSException();
+      aRv.StealExceptionFromJSContext(cx);
+      return;
+    }
+
+    // Step 2: Let buffer be the result of compressing chunk with cs's format
+    // and context.
+    // Step 3 - 5: (Done in CompressAndEnqueue)
+    ProcessTypedArraysFixed(
+        bufferSource,
+        [&](const Span<uint8_t>& aData) MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+          CompressAndEnqueue(cx, aData, ZLibFlush::No, aController, aRv);
+        });
+  }
+
+  // Step 4 of
+  // https://wicg.github.io/compression/#dom-compressionstream-compressionstream
+  // Let flushAlgorithm be an algorithm which takes no argument and runs the
+  // compress flush and enqueue algorithm with this.
+  MOZ_CAN_RUN_SCRIPT void FlushCallbackImpl(
+      TransformStreamDefaultController& aController,
+      ErrorResult& aRv) override {
+    AutoJSAPI jsapi;
+    if (!jsapi.Init(aController.GetParentObject())) {
+      aRv.ThrowUnknownError("Internal error");
+      return;
+    }
+    JSContext* cx = jsapi.cx();
+
+    // https://wicg.github.io/compression/#compress-flush-and-enqueue
+
+    // Step 1: Let buffer be the result of compressing an empty input with cs's
+    // format and context, with the finish flag.
+    // Step 2 - 4: (Done in CompressAndEnqueue)
+    CompressAndEnqueue(cx, Span<const uint8_t>(), ZLibFlush::Yes, aController,
+                       aRv);
+  }
+
+ private:
+  // Shared by:
+  // https://wicg.github.io/compression/#compress-and-enqueue-a-chunk
+  // https://wicg.github.io/compression/#compress-flush-and-enqueue
+  MOZ_CAN_RUN_SCRIPT void CompressAndEnqueue(
+      JSContext* aCx, Span<const uint8_t> aInput, ZLibFlush aFlush,
+      TransformStreamDefaultController& aController, ErrorResult& aRv) {
+    MOZ_ASSERT_IF(aFlush == ZLibFlush::Yes, !aInput.Length());
+
+    mZStream.avail_in = aInput.Length();
+    mZStream.next_in = const_cast<uint8_t*>(aInput.Elements());
+
+    JS::RootedVector<JSObject*> array(aCx);
+
+    do {
+      static uint16_t kBufferSize = 16384;
+      UniquePtr<uint8_t[], JS::FreePolicy> buffer(
+          static_cast<uint8_t*>(JS_malloc(aCx, kBufferSize)));
+      if (!buffer) {
+        aRv.ThrowTypeError("Out of memory");
+        return;
+      }
+
+      mZStream.avail_out = kBufferSize;
+      mZStream.next_out = buffer.get();
+
+      int8_t err = deflate(&mZStream, aFlush);
+
+      // From the manual: deflate() returns ...
+      switch (err) {
+        case Z_OK:
+        case Z_STREAM_END:
+        case Z_BUF_ERROR:
+          // * Z_OK if some progress has been made
+          // * Z_STREAM_END if all input has been consumed and all output has
+          // been produced (only when flush is set to Z_FINISH)
+          // * Z_BUF_ERROR if no progress is possible (for example avail_in or
+          // avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
+          // deflate() can be called again with more input and more output space
+          // to continue compressing.
+          //
+          // (But of course no input should be given after Z_FINISH)
+          break;
+        case Z_STREAM_ERROR:
+        default:
+          // * Z_STREAM_ERROR if the stream state was inconsistent
+          // (which is fatal)
+          MOZ_ASSERT_UNREACHABLE("Unexpected compression error code");
+          aRv.ThrowTypeError("Unexpected compression error");
+          return;
+      }
+
+      // Stream should end only when flushed, see above
+      // The reverse is not true as zlib may have big data to be flushed that is
+      // larger than the buffer size
+      MOZ_ASSERT_IF(err == Z_STREAM_END, aFlush == ZLibFlush::Yes);
+
+      // At this point we either exhausted the input or the output buffer
+      MOZ_ASSERT(!mZStream.avail_in || !mZStream.avail_out);
+
+      size_t written = kBufferSize - mZStream.avail_out;
+      if (!written) {
+        break;
+      }
+
+      // Step 3: If buffer is empty, return.
+      // (We'll implicitly return when the array is empty.)
+
+      // Step 4: Split buffer into one or more non-empty pieces and convert them
+      // into Uint8Arrays.
+      // (The buffer is 'split' by having a fixed sized buffer above.)
+
+      JS::Rooted<JSObject*> view(aCx, nsJSUtils::MoveBufferAsUint8Array(
+                                          aCx, written, std::move(buffer)));
+      if (!view || !array.append(view)) {
+        JS_ClearPendingException(aCx);
+        aRv.ThrowTypeError("Out of memory");
+        return;
+      }
+    } while (mZStream.avail_out == 0);
+    // From the manual:
+    // If deflate returns with avail_out == 0, this function must be called
+    // again with the same value of the flush parameter and more output space
+    // (updated avail_out)
+
+    // Step 5: For each Uint8Array array, enqueue array in cs's transform.
+    for (const auto& view : array) {
+      JS::Rooted<JS::Value> value(aCx, JS::ObjectValue(*view));
+      aController.Enqueue(aCx, value, aRv);
+      if (aRv.Failed()) {
+        return;
+      }
+    }
+  }
+
+  ~CompressionStreamAlgorithms() override { deflateEnd(&mZStream); };
+
+  z_stream mZStream = {};
+};
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(CompressionStreamAlgorithms,
+                                   TransformerAlgorithmsBase)
+NS_IMPL_ADDREF_INHERITED(CompressionStreamAlgorithms, TransformerAlgorithmsBase)
+NS_IMPL_RELEASE_INHERITED(CompressionStreamAlgorithms,
+                          TransformerAlgorithmsBase)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CompressionStreamAlgorithms)
+NS_INTERFACE_MAP_END_INHERITING(TransformerAlgorithmsBase)
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(CompressionStream, mGlobal, mStream)
+NS_IMPL_CYCLE_COLLECTING_ADDREF(CompressionStream)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(CompressionStream)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CompressionStream)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+CompressionStream::CompressionStream(nsISupports* aGlobal,
+                                     TransformStream& aStream)
+    : mGlobal(aGlobal), mStream(&aStream) {}
+
+CompressionStream::~CompressionStream() = default;
+
+JSObject* CompressionStream::WrapObject(JSContext* aCx,
+                                        JS::Handle<JSObject*> aGivenProto) {
+  return CompressionStream_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+// https://wicg.github.io/compression/#dom-compressionstream-compressionstream
+already_AddRefed<CompressionStream> CompressionStream::Constructor(
+    const GlobalObject& aGlobal, CompressionFormat aFormat, ErrorResult& aRv) {
+  // Step 1: If format is unsupported in CompressionStream, then throw a
+  // TypeError.
+  // XXX: Skipped as we are using enum for this
+
+  // Step 2 - 4: (Done in CompressionStreamAlgorithms)
+
+  // Step 5: Set this's transform to a new TransformStream.
+
+  // Step 6: Set up this's transform with transformAlgorithm set to
+  // transformAlgorithm and flushAlgorithm set to flushAlgorithm.
+  auto algorithms = MakeRefPtr<CompressionStreamAlgorithms>(aFormat);
+
+  RefPtr<TransformStream> stream =
+      TransformStream::CreateGeneric(aGlobal, *algorithms, aRv);
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+  return do_AddRef(new CompressionStream(aGlobal.GetAsSupports(), *stream));
+}
+
+already_AddRefed<ReadableStream> CompressionStream::Readable() const {
+  return do_AddRef(mStream->Readable());
+}
+
+already_AddRefed<WritableStream> CompressionStream::Writable() const {
+  return do_AddRef(mStream->Writable());
+}
+
+}  // namespace mozilla::dom