Rotate frames according to camera orientation

media/capture/video/linux/camera_config_chromeos.cc

 // Copyright 2016 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 "camera_facing_chromeos.h"
+#include "camera_config_chromeos.h"
 
 #include <base/files/file_util.h>
 #include <base/logging.h>
 #include <base/strings/stringprintf.h>
 #include <base/strings/string_number_conversions.h>
 #include <base/strings/string_piece.h>
 #include <base/strings/string_split.h>
 #include <base/strings/string_util.h>
 
 namespace media {
 
 namespace {
 
 // The value for each field in the enum matches the value in
 // /etc/camera/camera_characteristics.conf.
 enum LensFacing { FRONT = 0, BACK = 1 };
 
-bool GetCameraId(const base::StringPiece& sub_key, int* camera_id) {
+bool ParseCameraId(const base::StringPiece& sub_key, int* camera_id) {
   const base::StringPiece camera_id_prefix = "camera";
   if (!sub_key.starts_with(camera_id_prefix))
     return false;
   return base::StringToInt(sub_key.substr(camera_id_prefix.size()), camera_id);
 }
 }
 
 // /etc/camera/camera_characteristics.conf contains camera information which
 // driver cannot provide.
 static const char kCameraCharacteristicsConfigFile[] =
     "/etc/camera/camera_characteristics.conf";
 static const char kLensFacing[] = "lens_facing";
+static const char kSensorOrientation[] = "sensor_orientation";
 static const char kUsbVidPid[] = "usb_vid_pid";
 static const char kUsbPath[] = "usb_path";
+static const int kOrientationDefault = 0;
+static const int kCameraIdNotFound = -1;
 
-CameraFacingChromeOS::CameraFacingChromeOS() {
+CameraConfigChromeOS::CameraConfigChromeOS() {
   InitializeDeviceInfo(std::string(kCameraCharacteristicsConfigFile));
 }
 
-CameraFacingChromeOS::CameraFacingChromeOS(
+CameraConfigChromeOS::CameraConfigChromeOS(
     const std::string& config_file_path) {
   InitializeDeviceInfo(config_file_path);
 }
 
-CameraFacingChromeOS::~CameraFacingChromeOS() {}
+CameraConfigChromeOS::~CameraConfigChromeOS() {}
 
-VideoFacingMode CameraFacingChromeOS::GetCameraFacing(
+VideoFacingMode CameraConfigChromeOS::GetCameraFacing(
     const std::string& device_id,
     const std::string& model_id) const {
-  std::string usb_id = GetUsbId(device_id);
-  const auto& usb_id_to_camera_id_const = usb_id_to_camera_id_;
-  const auto& model_id_to_camera_id_const = model_id_to_camera_id_;
+  int camera_id = GetCameraId(device_id, model_id);
   const auto& camera_id_to_facing_const = camera_id_to_facing_;
-  auto usb_id_iter = usb_id_to_camera_id_const.find(usb_id);
-  int camera_id;
-  if (usb_id_iter == usb_id_to_camera_id_const.end()) {
-    // Can't find Usb ID. Fall back to use model_id.
-    auto model_id_iter = model_id_to_camera_id_const.find(model_id);
-    if (model_id_iter == model_id_to_camera_id_const.end()) {
-      DLOG(ERROR) << "Can't find model ID in config file: " << model_id;
-      return kLensFacingDefault;
-    }
-    camera_id = model_id_iter->second;
-  } else {
-    camera_id = usb_id_iter->second;
-  }
-
   auto camera_id_iter = camera_id_to_facing_const.find(camera_id);
   if (camera_id_iter == camera_id_to_facing_const.end()) {
     DLOG(ERROR) << "Can't find lens_facing of camera ID " << camera_id
                 << " in config file";
     return kLensFacingDefault;
   }
   return camera_id_iter->second;
 }
 
-std::string CameraFacingChromeOS::GetUsbId(const std::string& device_id) const {
+int CameraConfigChromeOS::GetOrientation(const std::string& device_id,
+                                         const std::string& model_id) const {
+  int camera_id = GetCameraId(device_id, model_id);
+  const auto& camera_id_to_orientation_const = camera_id_to_orientation_;
+  auto camera_id_iter = camera_id_to_orientation_const.find(camera_id);

[mcasas, 2017/01/23 21:44:57]

You shouldn't encode the type of the variable
or its const-ness in the name, so just
s/camera_id_iter/camera_id/ and
s/camera_id_to_orientation_const/camera_id_to_orientation/

(that's usual in Win programming, but not in Chromium)

[shenghao, 2017/01/24 14:29:52]

Done.

+  if (camera_id_iter == camera_id_to_orientation_const.end()) {
+    DLOG(ERROR) << "Can't find sensor_orientation of camera ID " << camera_id
+                << " in config file";
+    return kOrientationDefault;
+  }
+  return camera_id_iter->second;
+}
+
+int CameraConfigChromeOS::GetCameraId(const std::string& device_id,
+                                      const std::string& model_id) const {
+  std::string usb_id = GetUsbId(device_id);
+  const auto& usb_id_to_camera_id_const = usb_id_to_camera_id_;
+  const auto& model_id_to_camera_id_const = model_id_to_camera_id_;
+  auto usb_id_iter = usb_id_to_camera_id_const.find(usb_id);
+  int camera_id = 0;
+  if (usb_id_iter == usb_id_to_camera_id_const.end()) {
+    // Can't find Usb ID. Fall back to use model_id.

[mcasas, 2017/01/23 21:44:57]

s/model_id/|model_id|/

[shenghao, 2017/01/24 14:29:52]

Done.

+    auto model_id_iter = model_id_to_camera_id_const.find(model_id);
+    if (model_id_iter == model_id_to_camera_id_const.end()) {
+      DLOG(ERROR) << "Can't find model ID in config file: " << model_id;
+      return kCameraIdNotFound;
+    }
+    camera_id = model_id_iter->second;
+  } else {
+    camera_id = usb_id_iter->second;
+  }
+  return camera_id;

[mcasas, 2017/01/23 21:44:57]

The code in this and GetOrientation() methods is hard
to read due to the nested if()s. Prefer early return and
do not define aliases just for constness, e.g.:

  const auto& usb_id =...
  if (usb_id != usb_id_to_camera_id_.end())
    return usb_id->second;

  const model_id = ...
  if (model_id != model_id_to_camera_id_.end())
    return usb_id->second;

  DLOG(ERROR) << "..."
  return kCameraIdNotFound;

[shenghao, 2017/01/24 14:29:52]

Done, except that I have to keep the const temporary variable. Otherwise find()
will become a non-const method, which conflicts the constness of GetCameraId()

+}
+
+std::string CameraConfigChromeOS::GetUsbId(const std::string& device_id) const {
   // |device_id| is of the form "/dev/video2".  We want to retrieve "video2"
   // into |file_name|.
   const std::string device_dir = "/dev/";
   if (!base::StartsWith(device_id, device_dir, base::CompareCase::SENSITIVE)) {
     DLOG(ERROR) << "device_id is invalid: " << device_id;
     return std::string();
   }
   const std::string file_name = device_id.substr(device_dir.length());
 
   // Usb ID can be obtained by "readlink /sys/class/video4linux/video2/device".
@@ skipping 15 matching lines @@
       usb_part, ":", base::WhitespaceHandling::TRIM_WHITESPACE,
       base::SplitResult::SPLIT_WANT_ALL);
 
   if (usb_id_pieces.empty()) {
     DLOG(ERROR) << "Error after split: " << usb_part;
     return std::string();
   }
   return usb_id_pieces[0].as_string();
 }
 
-void CameraFacingChromeOS::InitializeDeviceInfo(
+void CameraConfigChromeOS::InitializeDeviceInfo(
     const std::string& config_file_path) {
   const base::FilePath path(config_file_path);
   std::string content;
   if (!base::ReadFileToString(path, &content)) {
     DPLOG(ERROR) << "ReadFileToString fails";
     return;
   }
   const std::vector<base::StringPiece> lines = base::SplitStringPiece(
       content, "\n", base::WhitespaceHandling::TRIM_WHITESPACE,
       base::SplitResult::SPLIT_WANT_NONEMPTY);
@@ skipping 13 matching lines @@
     const std::vector<base::StringPiece> sub_keys = base::SplitStringPiece(
         key, ".", base::WhitespaceHandling::TRIM_WHITESPACE,
         base::SplitResult::SPLIT_WANT_ALL);
 
     if (sub_keys.size() < 1) {
       DLOG(ERROR) << "No valid sub key exists. Line format is invalid: "
                   << line;
       continue;
     }
     int camera_id = 0;
-    if (!GetCameraId(sub_keys[0], &camera_id)) {
+    if (!ParseCameraId(sub_keys[0], &camera_id)) {
       DLOG(ERROR) << "Invalid sub key for camera id: " << sub_keys[0];
       continue;
     }
 
     if (sub_keys.size() == 2 && sub_keys[1] == kLensFacing) {
       int lens_facing = -1;
       if (!base::StringToInt(value, &lens_facing)) {
         DLOG(ERROR) << "Invalid value for lens_facing: " << value;
         continue;
       }
       switch (lens_facing) {
         case LensFacing::FRONT:
           camera_id_to_facing_[camera_id] =
               VideoFacingMode::MEDIA_VIDEO_FACING_USER;
           break;
         case LensFacing::BACK:
           camera_id_to_facing_[camera_id] =
               VideoFacingMode::MEDIA_VIDEO_FACING_ENVIRONMENT;
           break;
         default:
           DLOG(ERROR) << "Invalid value for lens_facing: " << lens_facing;
           continue;
       }
+    } else if (sub_keys.size() == 2 && sub_keys[1] == kSensorOrientation) {
+      int orientation = 0;
+      if (!base::StringToInt(value, &orientation)) {
+        DLOG(ERROR) << "Invalid value for sensor_orientation: " << value;
+        continue;
+      }
+      camera_id_to_orientation_[camera_id] = orientation;
     } else if (sub_keys.size() == 3 && sub_keys[2] == kUsbVidPid) {
       if (value.empty()) {
         DLOG(ERROR) << "model_id is empty";
         continue;
       }
       std::string model_id = value.as_string();
       std::transform(model_id.begin(), model_id.end(), model_id.begin(),
                      ::tolower);
       model_id_to_camera_id_[model_id] = camera_id;
     } else if (sub_keys.size() == 3 && sub_keys[2] == kUsbPath) {
       if (value.empty()) {
         DLOG(ERROR) << "usb_path is empty";
         continue;
       }
       usb_id_to_camera_id_[value.as_string()] = camera_id;
     }
     // Ignore unknown or unutilized attributes.
   }
 }
 
 }  // namespace media