[Experimental] Supporting OOPIF printing

services/pdf_compositor/pdf_compositor_impl.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/pdf_compositor/pdf_compositor_impl.h"
+
+#include <string.h>
+
+#include <utility>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/memory/shared_memory_handle.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/system/platform_handle.h"
+#include "printing/pdf_metafile_skia.h"
+#include "services/pdf_compositor/public/cpp/compositor_data.h"
+#include "skia/ext/SkFutureDrawable.h"
+#include "skia/ext/skia_utils_base.h"
+
+namespace pdf_compositor {
+
+PdfCompositorImpl::PdfCompositorImpl(
+    std::unique_ptr<service_manager::ServiceContextRef> service_ref)
+    : service_ref_(std::move(service_ref)) {}
+
+PdfCompositorImpl::~PdfCompositorImpl() = default;
+
+/*
+void PdfCompositorImpl::PrepareComposition(int frameId) {
+  painted_subframes_.clear();
+  pages_with_subframe_.clear();
+  pending_subframes_in_page_.clear();
+  SkFutureDrawable::resetDrawableRef();
+}*/
+
+void PdfCompositorImpl::PrepareSubframe(int subframe_id, int page_num) {
+  // Check whether this frame is already painted.
+  if (painted_subframes_.find(subframe_id) != painted_subframes_.end())
+    return;
+
+  // Need to wait for this subframe to finish painting.
+  pages_with_subframe_[subframe_id].insert(page_num);
+  pending_subframes_in_page_[page_num].insert(subframe_id);
+}
+
+void PdfCompositorImpl::AddSubFrameContent(
+    int subframe_id,
+    mojo::ScopedSharedBufferHandle sk_handle) {
+  base::SharedMemoryHandle memory_handle;
+  size_t memory_size = 0;
+  bool read_only_flag = false;
+
+  const MojoResult result = mojo::UnwrapSharedMemoryHandle(
+      std::move(sk_handle), &memory_handle, &memory_size, &read_only_flag);
+  DCHECK_EQ(MOJO_RESULT_OK, result);
+  DCHECK_GT(memory_size, 0u);
+
+  std::unique_ptr<base::SharedMemory> shm(
+      new base::SharedMemory(memory_handle, true));
+  if (!shm->Map(memory_size)) {
+    DLOG(ERROR) << "OnBufferCreated: Map failed.";
+    return;
+  }
+
+  size_t size = *((size_t*)shm->memory());
+  size_t off = 2 * sizeof(SkScalar) + sizeof(size_t);
+  std::unique_ptr<SkDrawable> d =
+      skia::ReadDrawable((char*)shm->memory() + off, size);
+
+  // Update the maps to remove dependecy on this subframe.
+  auto pages_entry = pages_with_subframe_.find(subframe_id);
+  if (pages_entry != pages_with_subframe_.end()) {
+    auto pages = pages_entry->second;
+    for (auto page : pages) {
+      auto frames_entry = pending_subframes_in_page_.find(page);
+      if (frames_entry != pending_subframes_in_page_.end()) {
+        // Page no longer depends on this frame.
+        if (frames_entry->second.size() == 1)
+          pending_subframes_in_page_.erase(frames_entry);
+        else
+          frames_entry->second.erase(subframe_id);
+      }
+    }
+    pages_with_subframe_.erase(pages_entry);
+  }
+  painted_subframes_.insert(subframe_id);
+
+  SkFutureDrawable::addDrawableRef(subframe_id, std::move(d));
+}
+
+void PdfCompositorImpl::IsReadyToComposite(
+    int page_num,
+    const mojom::PdfCompositor::IsReadyToCompositeCallback& callback) {
+  if (page_num == kPageRangeAll) {
+    // Need to check for all pages.
+    callback.Run(pages_with_subframe_.empty());
+  } else {
+    callback.Run(pending_subframes_in_page_.find(page_num) ==
+                 pending_subframes_in_page_.end());
+  }
+}
+
+void PdfCompositorImpl::CompositePdf(
+    mojo::ScopedSharedBufferHandle sk_handle,
+    const mojom::PdfCompositor::CompositePdfCallback& callback) {
+  DCHECK(sk_handle.is_valid());
+
+  // Check whether all the subframes are ready.
+  if (!pages_with_subframe_.empty()) {
+    // Should not happen.
+    return;
+  }
+
+  base::SharedMemoryHandle memory_handle;
+  size_t memory_size = 0;
+  bool read_only_flag = false;
+
+  const MojoResult result = mojo::UnwrapSharedMemoryHandle(
+      std::move(sk_handle), &memory_handle, &memory_size, &read_only_flag);
+  DCHECK_EQ(MOJO_RESULT_OK, result);
+  DCHECK_GT(memory_size, 0u);
+
+  std::unique_ptr<base::SharedMemory> shm(
+      new base::SharedMemory(memory_handle, true));
+  if (!shm->Map(memory_size)) {
+    DLOG(ERROR) << "OnBufferCreated: Map failed.";
+    return;
+  }
+
+  std::vector<uint8_t> ret_buf;
+  if (shm->mapped_size() == 0) {
+    callback.Run(mojo::ScopedSharedBufferHandle());
+    return;
+  }
+
+  std::unique_ptr<printing::PdfMetafileSkia> metafile(
+      new printing::PdfMetafileSkia(printing::PDF_SKIA_DOCUMENT_TYPE));
+  if (!metafile->InitFromPageDataBuffer((char*)shm->memory(), memory_size)) {
+    NOTREACHED() << "Invalid metafile header";
+    callback.Run(mojo::ScopedSharedBufferHandle());
+    return;
+  }
+
+  metafile->ConvertPagesToPdf();
+  metafile->GetDataAsVector((std::vector<char>*)&ret_buf);
+
+  mojo::ScopedSharedBufferHandle buffer =
+      mojo::SharedBufferHandle::Create(ret_buf.size());
+  CHECK(buffer.is_valid());
+
+  mojo::ScopedSharedBufferMapping mapping = buffer->Map(ret_buf.size());
+  CHECK(mapping);
+  std::copy(ret_buf.begin(), ret_buf.end(),
+            reinterpret_cast<char*>(mapping.get()));
+
+  callback.Run(std::move(buffer));
+}
+}  // namespace pdf_compositor