WebView autofill implementation

components/autofill/android/autofill_provider_android.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 "components/autofill/android/autofill_provider_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/memory/ptr_util.h"
+#include "components/autofill/android/form_data_android.h"
+#include "components/autofill/core/browser/autofill_handler_proxy.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
+#include "jni/AutofillProvider_jni.h"
+#include "ui/gfx/geometry/rect_f.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF16ToJavaString;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::JavaRef;
+using base::android::ScopedJavaLocalRef;
+using content::BrowserThread;
+using content::WebContents;
+using gfx::RectF;
+
+namespace autofill {
+
+const int kInvalidRequestId = -1;
+
+AutofillProviderAndroid::AutofillProviderAndroid(
+    const JavaRef<jobject>& jcaller,
+    content::WebContents* web_contents)
+    : id_(kInvalidRequestId), web_contents_(web_contents) {
+  JNIEnv* env = AttachCurrentThread();
+  java_ref_ = JavaObjectWeakGlobalRef(env, jcaller);
+  Java_AutofillProvider_setNativeAutofillProvider(
+      env, jcaller, reinterpret_cast<jlong>(this));
+}
+
+AutofillProviderAndroid::~AutofillProviderAndroid() {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+

[Mathieu, 2017/05/24 18:02:01]

// Remove the reference to this object on the Java side.

[michaelbai, 2017/05/26 23:12:06]

Done.

+  Java_AutofillProvider_setNativeAutofillProvider(env, obj, 0);
+}
+
+void AutofillProviderAndroid::OnQueryFormFieldAutofill(
+    AutofillHandlerProxy* handler,
+    int32_t id,
+    const FormData& form,
+    const FormFieldData& field,
+    const gfx::RectF& bounding_box) {
+  // The id isn't passed to Java side because Android API guarantees the
+  // response is always for current session, so we just use the current id
+  // in response, see OnAutofillAvailable.
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);

[Mathieu, 2017/05/24 18:02:01]

From their sample code, is it typical to query Android Autofill APIs from the UI
thread? Will it cause jank?

[michaelbai, 2017/05/24 20:57:54]

This isn't synchronous query and pretty safe to call in UI thread, also we are
not waiting for response by blocking UI thread.

+  id_ = id;
+
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+
+  form_ = base::MakeUnique<FormDataAndroid>(form);
+
+  size_t index;
+  if (!form_->GetFieldIndex(field, &index))
+    return;
+
+  gfx::Rect client_area = web_contents_->GetContainerBounds();
+  gfx::RectF transformed_bounding =
+      bounding_box + client_area.OffsetFromOrigin();
+
+  ScopedJavaLocalRef<jobject> formObj = form_->GetJavaPeer();

[Mathieu, 2017/05/24 18:02:01]

hacker case: form_obj

[michaelbai, 2017/05/26 23:12:07]

Done.

+  handler_ = handler->GetWeakPtr();
+  Java_AutofillProvider_startAutofillSession(
+      env, obj, formObj, index, transformed_bounding.x(),
+      transformed_bounding.y(), transformed_bounding.width(),
+      transformed_bounding.height());
+}
+
+void AutofillProviderAndroid::OnAutofillAvailable(JNIEnv* env,
+                                                  jobject jcaller,
+                                                  jobject formData) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (handler_) {
+    const FormData& form = form_->PullAutofillValues();
+    SendFormDataToRenderer(handler_.get(), id_, form);
+  }
+}
+
+void AutofillProviderAndroid::OnTextFieldDidChange(
+    AutofillHandlerProxy* handler,
+    const FormData& form,
+    const FormFieldData& field,
+    const base::TimeTicks& timestamp) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!ValidateHandler(handler))

[Mathieu, 2017/05/24 18:02:01]

This function would benefit from high-level comments, because there are quite a
few reasons for the early return

[michaelbai, 2017/05/26 23:12:06]

Could you suggest the comments? from my aspect, the code is clear, we don't need
to repeat what the code does.

+    return;
+
+  if (!form_->SimilarFormAs(form))

[Mathieu, 2017/05/24 18:02:01]

can you combine those in a big if statement for the early return

[michaelbai, 2017/05/26 23:12:06]

Done.

+    return;
+
+  size_t index;
+  if (!form_->GetSimilarFieldIndex(field, &index))
+    return;
+
+  form_->OnTextFieldDidChange(index, field.value);
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+
+  Java_AutofillProvider_onTextFieldDidChange(env, obj, index);
+}
+
+void AutofillProviderAndroid::OnWillSubmitForm(
+    AutofillHandlerProxy* handler,
+    const FormData& form,
+    const base::TimeTicks& timestamp) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!ValidateHandler(handler))
+    return;
+
+  if (!form_->SimilarFormAs(form))
+    return;
+
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+  Java_AutofillProvider_onWillSubmitForm(env, obj);
+}
+
+void AutofillProviderAndroid::OnFocusNoLongerOnForm(
+    AutofillHandlerProxy* handler) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!ValidateHandler(handler))
+    return;
+
+  OnFocusChanged(false, 0, RectF());
+}
+
+void AutofillProviderAndroid::OnFocusChanged(bool focus_on_form,
+                                             size_t index,
+                                             const gfx::RectF& bounding_box) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+
+  Java_AutofillProvider_onFocusChanged(
+      env, obj, focus_on_form, index, bounding_box.x(), bounding_box.y(),
+      bounding_box.width(), bounding_box.height());
+}
+
+void AutofillProviderAndroid::OnDidFillAutofillFormData(
+    AutofillHandlerProxy* handler,
+    const FormData& form,
+    base::TimeTicks timestamp) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (handler != handler_.get() || !form_ || !form_->SimilarFormAs(form))
+    return;
+
+  for (auto field : form.fields) {

[Mathieu, 2017/05/24 18:02:01]

const FormFieldData& ?

[michaelbai, 2017/05/24 20:57:54]

Interesting, do we have any guideline about when auto should be used or not?

[michaelbai, 2017/05/26 23:12:06]

OK, I found something about auto here
https://google.github.io/styleguide/cppguide.html#auto ,  from my reading, 
const auto& is encouraged in this case, you might thought the context isn't
clear, I changed to const FormFieldData

+    if (!field.is_autofilled)
+      continue;
+    OnTextFieldDidChange(handler, form, field, timestamp);
+  }
+}
+
+void AutofillProviderAndroid::Reset(AutofillHandlerProxy* handler) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (handler == handler_.get()) {
+    handler_.reset();
+    JNIEnv* env = AttachCurrentThread();
+    ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+    if (obj.is_null())
+      return;
+
+    Java_AutofillProvider_reset(env, obj);
+  }
+}
+
+bool AutofillProviderAndroid::ValidateHandler(AutofillHandlerProxy* handler) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  bool ret = handler == handler_.get();
+  if (!ret)
+    handler_.reset();
+  return ret;
+}
+
+bool RegisterAutofillProvider(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace autofill