Android: refactors printing code & adds a test

printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java

Index: printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
diff --git a/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java b/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
new file mode 100644
index 0000000000000000000000000000000000000000..1f1f27a757cad0de25f5ff99ad775dccaf8929b1
--- /dev/null
+++ b/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
@@ -0,0 +1,145 @@
+// Copyright 2013 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.
+
+package org.chromium.printing;
+
+import android.os.Bundle;
+import android.os.CancellationSignal;
+import android.os.ParcelFileDescriptor;
+import android.print.PageRange;
+import android.print.PrintAttributes;
+import android.print.PrintDocumentAdapter;
+import android.print.PrintDocumentAdapter.LayoutResultCallback;
+import android.print.PrintDocumentAdapter.WriteResultCallback;
+import android.print.PrintDocumentInfo;
+
+/**
+ * Wrapper for {@link PrintDocumentAdapter} for easier testing.
+ *
+ * Normally, {@link PrintDocumentAdapter#LayoutResultCallback} and
+ * {@link PrintDocumentAdapter#WriteResultCallback} don't have public constructors. This makes
+ * it impossible to subclass them, which is required to emulate calls to
+ * {@link PrintDocumentAdapter#onLayout} and {@link PrintDocumentAdapter#onWrite}. This class helps
+ * bypassing the limitation.
+ */
+public class PrintDocumentAdapterWrapper extends PrintDocumentAdapter {
+    private PdfGenerator mPdfGenerator;
+
+    public static interface PdfGenerator {
+        void onStart();
+        void onLayout(
+                PrintAttributes oldAttributes,
+                PrintAttributes newAttributes,
+                CancellationSignal cancellationSignal,
+                PrintDocumentAdapterWrapper.LayoutResultCallbackWrapper callback,
+                Bundle metadata);
+        void onWrite(
+                final PageRange[] ranges,
+                final ParcelFileDescriptor destination,
+                final CancellationSignal cancellationSignal,
+                final PrintDocumentAdapterWrapper.WriteResultCallbackWrapper callback);
+        void onFinish();
+    }
+
+    public static interface LayoutResultCallbackWrapper {
+        void onLayoutFinished(PrintDocumentInfo info, boolean changed);
+        void onLayoutFailed(CharSequence error);
+        void onLayoutCancelled();
+    }
+
+    public static interface WriteResultCallbackWrapper {
+        void onWriteFinished(PageRange[] pages);
+        void onWriteFailed(CharSequence error);
+        void onWriteCancelled();
+    }
+
+    public static class LayoutResultCallbackWrapperImpl implements LayoutResultCallbackWrapper {
+        private LayoutResultCallback mCallback = null;
+        public LayoutResultCallbackWrapperImpl(LayoutResultCallback callback) {
+            assert callback != null;
+            mCallback = callback;
+        }
+
+        @Override
+        public void onLayoutFinished(PrintDocumentInfo info, boolean changed) {
+            mCallback.onLayoutFinished(info, changed);
+        }
+
+        @Override
+        public void onLayoutFailed(CharSequence error) {
+            mCallback.onLayoutFailed(error);
+        }
+
+        @Override
+        public void onLayoutCancelled() {
+            mCallback.onLayoutCancelled();
+        }
+    }
+
+    public static class WriteResultCallbackWrapperImpl implements WriteResultCallbackWrapper {
+        private WriteResultCallback mCallback = null;
+        public WriteResultCallbackWrapperImpl(WriteResultCallback callback) {
+            assert callback != null;
+            mCallback = callback;
+        }
+
+        @Override
+        public void onWriteFinished(PageRange[] pages) {
+            mCallback.onWriteFinished(pages);
+        }
+
+        @Override
+        public void onWriteFailed(CharSequence error) {
+            mCallback.onWriteFailed(error);
+        }
+
+        @Override
+        public void onWriteCancelled() {
+            mCallback.onWriteCancelled();
+        }
+    }
+
+    public void setPdfGenerator(PdfGenerator pdfGenerator) {
+        mPdfGenerator = pdfGenerator;
+    }
+
+    /**
+     * Initiates the printing process within the framework
+     */
+    public void print(PrintManagerDelegate printManager, String title) {
+        printManager.print(title, this, null);
+    }
+
+    @Override
+    public void onStart() {
+        mPdfGenerator.onStart();
+    }
+
+    @Override
+    public void onLayout(
+            PrintAttributes oldAttributes,
+            PrintAttributes newAttributes,
+            CancellationSignal cancellationSignal,
+            LayoutResultCallback callback,
+            Bundle metadata) {
+        mPdfGenerator.onLayout(oldAttributes, newAttributes, cancellationSignal,
+                new LayoutResultCallbackWrapperImpl(callback), metadata);
+    }
+
+    @Override
+    public void onWrite(
+            final PageRange[] ranges,
+            final ParcelFileDescriptor destination,
+            final CancellationSignal cancellationSignal,
+            final WriteResultCallback callback) {
+        mPdfGenerator.onWrite(ranges, destination, cancellationSignal,
+                new WriteResultCallbackWrapperImpl(callback));
+    }
+
+    @Override
+    public void onFinish() {
+        super.onFinish();
+        mPdfGenerator.onFinish();
+    }
+}