The Tor Browser: widget/gonk/libui/VelocityControl.cpp@ac0c01689b40

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     1 /*

     2  * Copyright (C) 2012 The Android Open Source Project

     3  *

     4  * Licensed under the Apache License, Version 2.0 (the "License");

     5  * you may not use this file except in compliance with the License.

     6  * You may obtain a copy of the License at

     7  *

     8  *      http://www.apache.org/licenses/LICENSE-2.0

     9  *

    10  * Unless required by applicable law or agreed to in writing, software

    11  * distributed under the License is distributed on an "AS IS" BASIS,

    12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

    13  * See the License for the specific language governing permissions and

    14  * limitations under the License.

    15  */

    17 #define LOG_TAG "VelocityControl"

    18 //#define LOG_NDEBUG 0

    20 // Log debug messages about acceleration.

    21 #define DEBUG_ACCELERATION 0

    23 #include <math.h>

    24 #include <limits.h>

    26 #include "VelocityControl.h"

    27 #include <utils/BitSet.h>

    28 #include <utils/Timers.h>

    30 namespace android {

    32 // --- VelocityControl ---

    34 const nsecs_t VelocityControl::STOP_TIME;

    36 VelocityControl::VelocityControl() {

    37     reset();

    38 }

    40 void VelocityControl::setParameters(const VelocityControlParameters& parameters) {

    41     mParameters = parameters;

    42     reset();

    43 }

    45 void VelocityControl::reset() {

    46     mLastMovementTime = LLONG_MIN;

    47     mRawPosition.x = 0;

    48     mRawPosition.y = 0;

    49     mVelocityTracker.clear();

    50 }

    52 void VelocityControl::move(nsecs_t eventTime, float* deltaX, float* deltaY) {

    53     if ((deltaX && *deltaX) || (deltaY && *deltaY)) {

    54         if (eventTime >= mLastMovementTime + STOP_TIME) {

    55 #if DEBUG_ACCELERATION

    56             ALOGD("VelocityControl: stopped, last movement was %0.3fms ago",

    57                     (eventTime - mLastMovementTime) * 0.000001f);

    58 #endif

    59             reset();

    60         }

    62         mLastMovementTime = eventTime;

    63         if (deltaX) {

    64             mRawPosition.x += *deltaX;

    65         }

    66         if (deltaY) {

    67             mRawPosition.y += *deltaY;

    68         }

    69         mVelocityTracker.addMovement(eventTime, BitSet32(BitSet32::valueForBit(0)), &mRawPosition);

    71         float vx, vy;

    72         float scale = mParameters.scale;

    73         if (mVelocityTracker.getVelocity(0, &vx, &vy)) {

    74             float speed = hypotf(vx, vy) * scale;

    75             if (speed >= mParameters.highThreshold) {

    76                 // Apply full acceleration above the high speed threshold.

    77                 scale *= mParameters.acceleration;

    78             } else if (speed > mParameters.lowThreshold) {

    79                 // Linearly interpolate the acceleration to apply between the low and high

    80                 // speed thresholds.

    81                 scale *= 1 + (speed - mParameters.lowThreshold)

    82                         / (mParameters.highThreshold - mParameters.lowThreshold)

    83                         * (mParameters.acceleration - 1);

    84             }

    86 #if DEBUG_ACCELERATION

    87             ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): "

    88                     "vx=%0.3f, vy=%0.3f, speed=%0.3f, accel=%0.3f",

    89                     mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,

    90                     mParameters.acceleration,

    91                     vx, vy, speed, scale / mParameters.scale);

    92 #endif

    93         } else {

    94 #if DEBUG_ACCELERATION

    95             ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): unknown velocity",

    96                     mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,

    97                     mParameters.acceleration);

    98 #endif

    99         }

   101         if (deltaX) {

   102             *deltaX *= scale;

   103         }

   104         if (deltaY) {

   105             *deltaY *= scale;

   106         }

   107     }

   108 }

   110 } // namespace android

The Tor Browser / file revision

widget/gonk/libui/VelocityControl.cpp@ac0c01689b40

widget/gonk/libui/VelocityControl.cpp