Detect locally installed native Android payment apps.

chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
new file mode 100644
index 0000000000000000000000000000000000000000..adf0d2d026835fe3a8dcf2b49691d4dc34d6f6e4
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
@@ -0,0 +1,192 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.

[gone, 2017/01/03 19:20:03]

Happy new year!

[please use gerrit instead, 2017/01/04 17:27:53]

You too!

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.payments;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.graphics.drawable.Drawable;
+import android.os.Bundle;
+import android.os.Handler;
+import android.util.JsonWriter;
+
+import org.chromium.chrome.R;
+import org.chromium.payments.mojom.PaymentItem;
+import org.chromium.payments.mojom.PaymentMethodData;
+import org.chromium.ui.base.WindowAndroid;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/** A locally installed payment app. */

[gone, 2017/01/03 19:20:03]

nit: Maybe "interfaces with a locally installed payment app"?  It's a little
weird to say that this class is an app.

[please use gerrit instead, 2017/01/04 17:27:53]

Done.

+public class AndroidPaymentApp extends PaymentInstrument implements PaymentApp,
+        WindowAndroid.IntentCallback {
+    private static final String METHOD_NAME_EXTRA = "methodName";

[gone, 2017/01/03 19:20:03]

nit: Consider prefixing these with EXTRA_ instead of suffixing them.  It's a
more common pattern in the codebase and groups them together more clearly.

[please use gerrit instead, 2017/01/04 17:27:53]

Done.

+    private static final String DATA_EXTRA = "data";
+    private static final String ORIGIN_EXTRA = "origin";
+    private static final String DETAILS_EXTRA = "details";
+    private static final String INSTRUMENT_DETAILS_EXTRA = "instrumentDetails";
+    private static final String EMPTY_JSON_DATA = "{}";
+
+    private final Handler mHandler;
+    private final WindowAndroid mWindow;
+    private final Intent mPayIntent;
+    private final Set<String> mMethodNames;
+    private String mIsReadyToPayService;
+    private InstrumentDetailsCallback mInstrumentDetailsCallback;
+
+    public AndroidPaymentApp(WindowAndroid window, String packageName, String activity,
+            String label, Drawable icon) {
+        super(packageName, label, null, icon);
+        mHandler = new Handler();
+        mWindow = window;
+        mPayIntent = new Intent();
+        mPayIntent.setClassName(packageName, activity);
+        mMethodNames = new HashSet<>();
+    }
+
+    public void addMethodName(String methodName) {

[gone, 2017/01/03 19:20:03]

Javadocs for public methods.  Findbugs might complain otherwise.

[please use gerrit instead, 2017/01/04 17:27:53]

Done.

+        mMethodNames.add(methodName);
+    }
+
+    public void setIsReadyToPayService(String service) {
+        mIsReadyToPayService = service;
+    }
+
+    @Override
+    public void getInstruments(Map<String, PaymentMethodData> methodData, String origin,
+            final InstrumentsCallback callback) {
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                List<PaymentInstrument> instruments = new ArrayList<>();
+                instruments.add(AndroidPaymentApp.this);
+                callback.onInstrumentsReady(AndroidPaymentApp.this, instruments);
+            }
+        });
+    }
+
+    @Override
+    public boolean supportsMethodsAndData(Map<String, PaymentMethodData> methodsAndData) {
+        assert methodsAndData != null;
+        Set<String> methodNames = new HashSet<>(methodsAndData.keySet());
+        methodNames.retainAll(getAppMethodNames());
+        return !methodNames.isEmpty();
+    }
+
+    @Override
+    public String getAppIdentifier() {
+        return getIdentifier();
+    }
+
+    @Override
+    public Set<String> getAppMethodNames() {
+        return Collections.unmodifiableSet(mMethodNames);
+    }
+
+    @Override
+    public Set<String> getInstrumentMethodNames() {
+        return Collections.unmodifiableSet(mMethodNames);

[gone, 2017/01/03 19:20:03]

Is this function's return value always going to match getAppMethodNames?  Should
one call the other?

[please use gerrit instead, 2017/01/04 17:27:53]

Done.

+    }
+
+    @Override
+    public void invokePaymentApp(String merchantName, String origin, PaymentItem total,
+            List<PaymentItem> cart, Map<String, PaymentMethodData> methodDataMap,
+            InstrumentDetailsCallback callback) {
+        assert !mMethodNames.isEmpty();
+
+        Bundle extras = new Bundle();
+        extras.putString(ORIGIN_EXTRA, origin);
+
+        String methodName = mMethodNames.iterator().next();
+        extras.putString(METHOD_NAME_EXTRA, methodName);
+
+        PaymentMethodData methodData = methodDataMap.get(methodName);
+        extras.putString(
+                DATA_EXTRA, methodData == null ? EMPTY_JSON_DATA : methodData.stringifiedData);
+
+        String details = serializeDetails(total, cart);
+        extras.putString(DETAILS_EXTRA, details == null ? EMPTY_JSON_DATA : details);
+        mPayIntent.putExtras(extras);
+
+        mInstrumentDetailsCallback = callback;
+        if (!mWindow.showIntent(mPayIntent, this, R.string.payments_android_app_error)) {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    mInstrumentDetailsCallback.onInstrumentDetailsError();
+                }
+            });
+        }
+    }
+
+    private static String serializeDetails(PaymentItem total, List<PaymentItem> cart) {
+        StringWriter stringWriter = new StringWriter();
+        JsonWriter json = new JsonWriter(stringWriter);
+        try {
+            // details {{{
+            json.beginObject();
+
+            // total {{{
+            json.name("total");
+            serializePaymentItem(json, total);
+            // }}} total
+
+            // displayitems {{{
+            if (cart != null) {
+                json.name("displayItems").beginArray();
+                for (int i = 0; i < cart.size(); i++) {
+                    serializePaymentItem(json, cart.get(i));
+                }
+                json.endArray();
+            }
+            // }}} displayItems
+
+            json.endObject();
+            // }}} details
+        } catch (IOException e) {
+            return null;
+        }
+
+        return stringWriter.toString();
+    }
+
+    private static void serializePaymentItem(JsonWriter json, PaymentItem item) throws IOException {
+        // item {{{
+        json.beginObject();
+        json.name("label").value(item.label);
+
+        // amount {{{
+        json.name("amount").beginObject();
+        json.name("currency").value(item.amount.currency);
+        json.name("value").value(item.amount.value);
+        json.endObject();
+        // }}} amount
+
+        json.endObject();
+        // }}} item
+    }
+
+    @Override
+    public void onIntentCompleted(WindowAndroid window, int resultCode, Intent data) {
+        mWindow.removeIntentCallback(this);
+        if (data == null || data.getExtras() == null || resultCode != Activity.RESULT_OK) {
+            mInstrumentDetailsCallback.onInstrumentDetailsError();
+        } else {
+            mInstrumentDetailsCallback.onInstrumentDetailsReady(
+                    data.getExtras().getString(METHOD_NAME_EXTRA),
+                    data.getExtras().getString(INSTRUMENT_DETAILS_EXTRA));
+        }
+        mInstrumentDetailsCallback = null;
+    }
+
+    @Override
+    public void dismissInstrument() {}
+}