1 files changed, 167 insertions, 0 deletions
diff --git a/layout/printing/DrawEventRecorder.h b/layout/printing/DrawEventRecorder.h
new file mode 100644
index 0000000000..79eaa65ef4
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+++ b/layout/printing/DrawEventRecorder.h
@@ -0,0 +1,167 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_layout_printing_DrawEventRecorder_h
+#define mozilla_layout_printing_DrawEventRecorder_h
+
+#include <memory>
+
+#include "mozilla/gfx/DrawEventRecorder.h"
+#include "mozilla/gfx/RecordingTypes.h"
+#include "prio.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace layout {
+
+class PRFileDescStream final : public mozilla::gfx::EventStream {
+  // Most writes, as seen in the print IPC use case, are very small (<32 bytes),
+  // with a small number of very large (>40KB) writes. Writes larger than this
+  // value are not buffered.
+  static const size_t kBufferSize = 1024;
+
+ public:
+  PRFileDescStream()
+      : mFd(nullptr), mBuffer(nullptr), mBufferPos(0), mGood(true) {}
+  PRFileDescStream(const PRFileDescStream& other) = delete;
+  ~PRFileDescStream() { Close(); }
+
+  void OpenFD(PRFileDesc* aFd) {
+    MOZ_DIAGNOSTIC_ASSERT(!IsOpen());
+    mFd = aFd;
+    mGood = !!mFd;
+    mBuffer.reset(new uint8_t[kBufferSize]);
+    mBufferPos = 0;
+  }
+
+  void Close() {
+    // We need to be API compatible with std::ostream, and so we silently handle
+    // closes on a closed FD.
+    if (IsOpen()) {
+      Flush();
+      PR_Close(mFd);
+      mFd = nullptr;
+      mBuffer.reset();
+      mBufferPos = 0;
+    }
+  }
+
+  bool IsOpen() { return mFd != nullptr; }
+
+  void Flush() {
+    // See comment in Close().
+    if (IsOpen() && mBufferPos > 0) {
+      PRInt32 length =
+          PR_Write(mFd, static_cast<const void*>(mBuffer.get()), mBufferPos);
+      mGood = length >= 0 && static_cast<size_t>(length) == mBufferPos;
+      mBufferPos = 0;
+    }
+  }
+
+  void Seek(PRInt64 aOffset, PRSeekWhence aWhence) {
+    Flush();
+    PRInt64 pos = PR_Seek64(mFd, aOffset, aWhence);
+    mGood = pos != -1;
+  }
+
+  void write(const char* aData, size_t aSize) override {
+    if (!good()) {
+      return;
+    }
+
+    // See comment in Close().
+    if (IsOpen()) {
+      // If we're writing more data than could ever fit in our buffer, flush the
+      // buffer and write directly.
+      if (aSize > kBufferSize) {
+        Flush();
+        PRInt32 length = PR_Write(mFd, static_cast<const void*>(aData), aSize);
+        mGood = length >= 0 && static_cast<size_t>(length) == aSize;
+        // If our write could fit in our buffer, but doesn't because the buffer
+        // is partially full, write to the buffer, flush the buffer, and then
+        // write the rest of the data to the buffer.
+      } else if (aSize > AvailableBufferSpace()) {
+        size_t length = AvailableBufferSpace();
+        WriteToBuffer(aData, length);
+        Flush();
+
+        WriteToBuffer(aData + length, aSize - length);
+        // Write fits in the buffer.
+      } else {
+        WriteToBuffer(aData, aSize);
+      }
+    }
+  }
+
+  void read(char* aOut, size_t aSize) override {
+    if (!good()) {
+      return;
+    }
+
+    Flush();
+    PRInt32 res = PR_Read(mFd, static_cast<void*>(aOut), aSize);
+    mGood = res >= 0 && (static_cast<size_t>(res) == aSize);
+  }
+
+  bool good() final { return mGood; }
+
+  void SetIsBad() final { mGood = false; }
+
+ private:
+  size_t AvailableBufferSpace() { return kBufferSize - mBufferPos; }
+
+  void WriteToBuffer(const char* aData, size_t aSize) {
+    MOZ_ASSERT(aSize <= AvailableBufferSpace());
+    memcpy(mBuffer.get() + mBufferPos, aData, aSize);
+    mBufferPos += aSize;
+  }
+
+  PRFileDesc* mFd;
+  std::unique_ptr<uint8_t[]> mBuffer;
+  size_t mBufferPos;
+  bool mGood;
+};
+
+class DrawEventRecorderPRFileDesc final : public gfx::DrawEventRecorderPrivate {
+ public:
+  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(DrawEventRecorderPRFileDesc, override)
+  explicit DrawEventRecorderPRFileDesc() = default;
+  ~DrawEventRecorderPRFileDesc();
+
+  void RecordEvent(const gfx::RecordedEvent& aEvent) override;
+
+  /**
+   * Returns whether a recording file is currently open.
+   */
+  bool IsOpen();
+
+  /**
+   * Opens the recorder with the provided PRFileDesc *.
+   */
+  void OpenFD(PRFileDesc* aFd);
+
+  /**
+   * Closes the file so that it can be processed. The recorder does NOT forget
+   * which objects it has recorded. This can be used with OpenNew, so that a
+   * recording can be processed in chunks. The file must be open.
+   */
+  void Close();
+
+  void AddDependentSurface(uint64_t aDependencyId) override;
+  nsTArray<uint64_t>&& TakeDependentSurfaces();
+
+ private:
+  void Flush() override;
+
+  PRFileDescStream mOutputStream;
+  nsTArray<uint64_t> mDependentSurfaces;
+};
+
+}  // namespace layout
+
+}  // namespace mozilla
+
+#endif /* mozilla_layout_printing_DrawEventRecorder_h */