flutter_flutter/ui/gfx/android/view_configuration.cc

// Copyright 2014 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 "ui/gfx/android/view_configuration.h"

#include "base/android/jni_android.h"
#include "base/lazy_instance.h"
#include "base/threading/non_thread_safe.h"
#include "jni/ViewConfigurationHelper_jni.h"

using base::android::AttachCurrentThread;
using base::android::GetApplicationContext;

namespace gfx {

namespace {

struct ViewConfigurationData {
  ViewConfigurationData()
      : double_tap_timeout_in_ms_(0),
        long_press_timeout_in_ms_(0),
        tap_timeout_in_ms_(0),
        scroll_friction_(1.f),
        max_fling_velocity_in_pixels_s_(0),
        min_fling_velocity_in_pixels_s_(0),
        touch_slop_in_pixels_(0),
        double_tap_slop_in_pixels_(0),
        min_scaling_span_in_pixels_(0),
        min_scaling_touch_major_in_pixels_(0) {
    JNIEnv* env = AttachCurrentThread();
    j_view_configuration_helper_.Reset(
        Java_ViewConfigurationHelper_createWithListener(
            env, base::android::GetApplicationContext()));

    double_tap_timeout_in_ms_ =
        Java_ViewConfigurationHelper_getDoubleTapTimeout(env);
    long_press_timeout_in_ms_ =
        Java_ViewConfigurationHelper_getLongPressTimeout(env);
    tap_timeout_in_ms_ = Java_ViewConfigurationHelper_getTapTimeout(env);
    scroll_friction_ = Java_ViewConfigurationHelper_getScrollFriction(env);

    jobject obj = j_view_configuration_helper_.obj();
    Update(
        Java_ViewConfigurationHelper_getScaledMaximumFlingVelocity(env, obj),
        Java_ViewConfigurationHelper_getScaledMinimumFlingVelocity(env, obj),
        Java_ViewConfigurationHelper_getScaledTouchSlop(env, obj),
        Java_ViewConfigurationHelper_getScaledDoubleTapSlop(env, obj),
        Java_ViewConfigurationHelper_getScaledMinScalingSpan(env, obj),
        Java_ViewConfigurationHelper_getScaledMinScalingTouchMajor(env, obj));
  }

  ~ViewConfigurationData() {}

  void SynchronizedUpdate(int scaled_maximum_fling_velocity,
                          int scaled_minimum_fling_velocity,
                          int scaled_touch_slop,
                          int scaled_double_tap_slop,
                          int scaled_min_scaling_span,
                          int scaled_min_scaling_touch_major) {
    base::AutoLock autolock(lock_);
    Update(scaled_maximum_fling_velocity,
           scaled_minimum_fling_velocity,
           scaled_touch_slop,
           scaled_double_tap_slop,
           scaled_min_scaling_span,
           scaled_min_scaling_touch_major);
  }

  int double_tap_timeout_in_ms() const { return double_tap_timeout_in_ms_; }
  int long_press_timeout_in_ms() const { return long_press_timeout_in_ms_; }
  int tap_timeout_in_ms() const { return tap_timeout_in_ms_; }
  float scroll_friction() const { return scroll_friction_; }

  int max_fling_velocity_in_pixels_s() {
    base::AutoLock autolock(lock_);
    return max_fling_velocity_in_pixels_s_;
  }

  int min_fling_velocity_in_pixels_s() {
    base::AutoLock autolock(lock_);
    return min_fling_velocity_in_pixels_s_;
  }

  int touch_slop_in_pixels() {
    base::AutoLock autolock(lock_);
    return touch_slop_in_pixels_;
  }

  int double_tap_slop_in_pixels() {
    base::AutoLock autolock(lock_);
    return double_tap_slop_in_pixels_;
  }

  int min_scaling_span_in_pixels() {
    base::AutoLock autolock(lock_);
    return min_scaling_span_in_pixels_;
  }

  int min_scaling_touch_major_in_pixels() {
    base::AutoLock autolock(lock_);
    return min_scaling_touch_major_in_pixels_;
  }

 private:
  void Update(int scaled_maximum_fling_velocity,
              int scaled_minimum_fling_velocity,
              int scaled_touch_slop,
              int scaled_double_tap_slop,
              int scaled_min_scaling_span,
              int scaled_min_scaling_touch_major) {
    DCHECK_LE(scaled_minimum_fling_velocity, scaled_maximum_fling_velocity);
    max_fling_velocity_in_pixels_s_ = scaled_maximum_fling_velocity;
    min_fling_velocity_in_pixels_s_ = scaled_minimum_fling_velocity;
    touch_slop_in_pixels_ = scaled_touch_slop;
    double_tap_slop_in_pixels_ = scaled_double_tap_slop;
    min_scaling_span_in_pixels_ = scaled_min_scaling_span;
    min_scaling_touch_major_in_pixels_ = scaled_min_scaling_touch_major;
  }

  base::Lock lock_;
  base::android::ScopedJavaGlobalRef<jobject> j_view_configuration_helper_;

  // These values will remain constant throughout the lifetime of the app, so
  // read-access needn't be synchronized.
  int double_tap_timeout_in_ms_;
  int long_press_timeout_in_ms_;
  int tap_timeout_in_ms_;
  float scroll_friction_;

  // These values may vary as view-specific parameters (DPI scale) are changed,
  // so read/write access must be synchronized.
  int max_fling_velocity_in_pixels_s_;
  int min_fling_velocity_in_pixels_s_;
  int touch_slop_in_pixels_;
  int double_tap_slop_in_pixels_;
  int min_scaling_span_in_pixels_;
  int min_scaling_touch_major_in_pixels_;

 private:
  DISALLOW_COPY_AND_ASSIGN(ViewConfigurationData);
};

// Leaky to allow access from any thread.
base::LazyInstance<ViewConfigurationData>::Leaky g_view_configuration =
    LAZY_INSTANCE_INITIALIZER;

}  // namespace

static void UpdateSharedViewConfiguration(JNIEnv* env,
                                          jobject obj,
                                          jint scaled_maximum_fling_velocity,
                                          jint scaled_minimum_fling_velocity,
                                          jint scaled_touch_slop,
                                          jint scaled_double_tap_slop,
                                          jint scaled_min_scaling_span,
                                          jint scaled_min_scaling_touch_major) {
  g_view_configuration.Get().SynchronizedUpdate(scaled_maximum_fling_velocity,
                                                scaled_minimum_fling_velocity,
                                                scaled_touch_slop,
                                                scaled_double_tap_slop,
                                                scaled_min_scaling_span,
                                                scaled_min_scaling_touch_major);
}

int ViewConfiguration::GetDoubleTapTimeoutInMs() {
  return g_view_configuration.Get().double_tap_timeout_in_ms();
}

int ViewConfiguration::GetLongPressTimeoutInMs() {
  return g_view_configuration.Get().long_press_timeout_in_ms();
}

int ViewConfiguration::GetTapTimeoutInMs() {
  return g_view_configuration.Get().tap_timeout_in_ms();
}

float ViewConfiguration::GetScrollFriction() {
  return g_view_configuration.Get().scroll_friction();
}

int ViewConfiguration::GetMaximumFlingVelocityInPixelsPerSecond() {
  return g_view_configuration.Get().max_fling_velocity_in_pixels_s();
}

int ViewConfiguration::GetMinimumFlingVelocityInPixelsPerSecond() {
  return g_view_configuration.Get().min_fling_velocity_in_pixels_s();
}

int ViewConfiguration::GetTouchSlopInPixels() {
  return g_view_configuration.Get().touch_slop_in_pixels();
}

int ViewConfiguration::GetDoubleTapSlopInPixels() {
  return g_view_configuration.Get().double_tap_slop_in_pixels();
}

int ViewConfiguration::GetMinScalingSpanInPixels() {
  return g_view_configuration.Get().min_scaling_span_in_pixels();
}

int ViewConfiguration::GetMinScalingTouchMajorInPixels() {
  return g_view_configuration.Get().min_scaling_touch_major_in_pixels();
}

bool ViewConfiguration::RegisterViewConfiguration(JNIEnv* env) {
  return RegisterNativesImpl(env);
}

}  // namespace gfx