From b76af93ab56bc3296e01e65a6fe64a0622ab5b91 Mon Sep 17 00:00:00 2001
From: Jerry Zhang <zhangjerry@google.com>
Date: Tue, 22 May 2018 12:08:35 -0700
Subject: recovery: Add ability to interrupt UI

Normally calling a UI method will block
indefinitely until the UI is actually
used. This creates a method to interrupt
the UI, causing waitKey to return -2. This
in turn, will cause ShowMenu to return -2.
This allows switching between recovery and
fastbootd via usb commands.

Test: adb shell /data/nativetest64/recovery_unit_test/recovery_unit_test
Bug: 78793464
Change-Id: I4c6c9aa18d79070877841a5c9818acf723fa6096
---
 ui.cpp | 85 ++++++++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 62 insertions(+), 23 deletions(-)

(limited to 'ui.cpp')

diff --git a/ui.cpp b/ui.cpp
index 6c91d01b8..a2c160f7a 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -58,6 +58,7 @@ RecoveryUI::RecoveryUI()
       touch_screen_allowed_(false),
       kTouchLowThreshold(RECOVERY_UI_TOUCH_LOW_THRESHOLD),
       kTouchHighThreshold(RECOVERY_UI_TOUCH_HIGH_THRESHOLD),
+      key_interrupted_(false),
       key_queue_len(0),
       key_last_down(-1),
       key_long_press(false),
@@ -404,34 +405,69 @@ void RecoveryUI::EnqueueKey(int key_code) {
   }
 }
 
+void RecoveryUI::SetScreensaverState(ScreensaverState state) {
+  switch (state) {
+    case ScreensaverState::NORMAL:
+      if (android::base::WriteStringToFile(std::to_string(brightness_normal_value_),
+                                           brightness_file_)) {
+        screensaver_state_ = ScreensaverState::NORMAL;
+        LOG(INFO) << "Brightness: " << brightness_normal_value_ << " (" << brightness_normal_
+                  << "%)";
+      } else {
+        LOG(ERROR) << "Unable to set brightness to normal";
+      }
+      break;
+    case ScreensaverState::DIMMED:
+      if (android::base::WriteStringToFile(std::to_string(brightness_dimmed_value_),
+                                           brightness_file_)) {
+        LOG(INFO) << "Brightness: " << brightness_dimmed_value_ << " (" << brightness_dimmed_
+                  << "%)";
+        screensaver_state_ = ScreensaverState::DIMMED;
+      } else {
+        LOG(ERROR) << "Unable to set brightness to dim";
+      }
+      break;
+    case ScreensaverState::OFF:
+      if (android::base::WriteStringToFile("0", brightness_file_)) {
+        LOG(INFO) << "Brightness: 0 (off)";
+        screensaver_state_ = ScreensaverState::OFF;
+      } else {
+        LOG(ERROR) << "Unable to set brightness to off";
+      }
+      break;
+    default:
+      LOG(ERROR) << "Invalid screensaver state";
+  }
+}
+
 int RecoveryUI::WaitKey() {
   std::unique_lock<std::mutex> lk(key_queue_mutex);
 
+  // Check for a saved key queue interruption.
+  if (key_interrupted_) {
+    SetScreensaverState(ScreensaverState::NORMAL);
+    return static_cast<int>(KeyError::INTERRUPTED);
+  }
+
   // Time out after UI_WAIT_KEY_TIMEOUT_SEC, unless a USB cable is
   // plugged in.
   do {
-    std::cv_status rc = std::cv_status::no_timeout;
-    while (key_queue_len == 0 && rc != std::cv_status::timeout) {
-      rc = key_queue_cond.wait_for(lk, std::chrono::seconds(UI_WAIT_KEY_TIMEOUT_SEC));
+    bool rc = key_queue_cond.wait_for(lk, std::chrono::seconds(UI_WAIT_KEY_TIMEOUT_SEC), [this] {
+      return this->key_queue_len != 0 || key_interrupted_;
+    });
+    if (key_interrupted_) {
+      SetScreensaverState(ScreensaverState::NORMAL);
+      return static_cast<int>(KeyError::INTERRUPTED);
     }
-
     if (screensaver_state_ != ScreensaverState::DISABLED) {
-      if (rc == std::cv_status::timeout) {
+      if (!rc) {
         // Lower the brightness level: NORMAL -> DIMMED; DIMMED -> OFF.
         if (screensaver_state_ == ScreensaverState::NORMAL) {
-          if (android::base::WriteStringToFile(std::to_string(brightness_dimmed_value_),
-                                               brightness_file_)) {
-            LOG(INFO) << "Brightness: " << brightness_dimmed_value_ << " (" << brightness_dimmed_
-                      << "%)";
-            screensaver_state_ = ScreensaverState::DIMMED;
-          }
+          SetScreensaverState(ScreensaverState::DIMMED);
         } else if (screensaver_state_ == ScreensaverState::DIMMED) {
-          if (android::base::WriteStringToFile("0", brightness_file_)) {
-            LOG(INFO) << "Brightness: 0 (off)";
-            screensaver_state_ = ScreensaverState::OFF;
-          }
+          SetScreensaverState(ScreensaverState::OFF);
         }
-      } else if (screensaver_state_ != ScreensaverState::NORMAL) {
+      } else {
         // Drop the first key if it's changing from OFF to NORMAL.
         if (screensaver_state_ == ScreensaverState::OFF) {
           if (key_queue_len > 0) {
@@ -440,17 +476,12 @@ int RecoveryUI::WaitKey() {
         }
 
         // Reset the brightness to normal.
-        if (android::base::WriteStringToFile(std::to_string(brightness_normal_value_),
-                                             brightness_file_)) {
-          screensaver_state_ = ScreensaverState::NORMAL;
-          LOG(INFO) << "Brightness: " << brightness_normal_value_ << " (" << brightness_normal_
-                    << "%)";
-        }
+        SetScreensaverState(ScreensaverState::NORMAL);
       }
     }
   } while (IsUsbConnected() && key_queue_len == 0);
 
-  int key = -1;
+  int key = static_cast<int>(KeyError::TIMED_OUT);
   if (key_queue_len > 0) {
     key = key_queue[0];
     memcpy(&key_queue[0], &key_queue[1], sizeof(int) * --key_queue_len);
@@ -458,6 +489,14 @@ int RecoveryUI::WaitKey() {
   return key;
 }
 
+void RecoveryUI::InterruptKey() {
+  {
+    std::lock_guard<std::mutex> lg(key_queue_mutex);
+    key_interrupted_ = true;
+  }
+  key_queue_cond.notify_one();
+}
+
 bool RecoveryUI::IsUsbConnected() {
   int fd = open("/sys/class/android_usb/android0/state", O_RDONLY);
   if (fd < 0) {
-- 
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