Print directly to CUPS using the IPP APIs

printing/printed_document_chromeos.cc

+// Copyright 2016 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 "printing/printed_document.h"
+
+#include "base/logging.h"
+#include "printing/page_number.h"
+#include "printing/printed_page.h"
+
+#if defined(USE_CUPS)
+#include "printing/printing_context_chromeos.h"
+#endif  // USE_CUPS

[Lei Zhang, 2016/07/25 21:06:04]

So some of the printing code does not set the best example. This should be //
defined(USE_CUPS). i.e. #if $FOO should be mirrored by // $FOO.

Though in this particular case, I'd say don't even bother because:
1) there's no nesting
2) the #if is very close, so it's already obvious what this #endif pairs with.

Line 26 below should have the comment because nesting.
Line 44 below should have the comment because it's a bit far away from the #if.

[skau, 2016/07/27 00:16:47]

Done.

+
+namespace printing {
+
+void PrintedDocument::RenderPrintedPage(const PrintedPage& page,
+                                        PrintingContext* context) const {
+#if defined(USE_CUPS)
+#if defined(NDEBUG)
+  {
+    // Make sure the page is from our list.
+    base::AutoLock lock(lock_);
+    DCHECK(&page == mutable_.pages_.find(page.page_number() - 1)->second.get());
+  }
+#endif  // NDEBUG
+
+  DCHECK(context);
+
+  {
+    base::AutoLock lock(lock_);
+    if (page.page_number() - 1 == mutable_.first_page) {
+      std::vector<char> buffer;
+
+      if (page.metafile()->GetDataAsVector(&buffer)) {
+        static_cast<PrintingContextChromeos*>(context)->StreamData(buffer);
+      } else {
+        LOG(WARNING) << "Failed to read data from metafile";
+      }
+    }
+  }
+#else
+  NOTREACHED();
+#endif  // USE_CUPS
+}
+
+}  // namespace printing