Move V4L2 code into a webcam helper class.

extensions/browser/api/webcam_private/v4l2_webcam.cc

+// Copyright 2015 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 "extensions/browser/api/webcam_private/v4l2_webcam.h"
+
+#include <fcntl.h>
+#include <linux/uvcvideo.h>
+#include <linux/videodev2.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "base/posix/eintr_wrapper.h"
+
+#define V4L2_CID_PAN_SPEED (V4L2_CID_CAMERA_CLASS_BASE+32)
+#define V4L2_CID_TILT_SPEED (V4L2_CID_CAMERA_CLASS_BASE+33)
+#define V4L2_CID_PANTILT_CMD (V4L2_CID_CAMERA_CLASS_BASE+34)
+
+// GUID of the Extension Unit for Logitech CC3300e motor control:
+// {212de5ff-3080-2c4e-82d9-f587d00540bd}
+#define UVC_GUID_LOGITECH_CC3000E_MOTORS          \
+ {0x21, 0x2d, 0xe5, 0xff, 0x30, 0x80, 0x2c, 0x4e, \
+  0x82, 0xd9, 0xf5, 0x87, 0xd0, 0x05, 0x40, 0xbd}
+
+#define LOGITECH_MOTORCONTROL_PANTILT_CMD 2
+
+namespace {
+const int kLogitechMenuIndexGoHome = 2;
+
+const uvc_menu_info kLogitechCmdMenu[] = {
+  {1, "Set Preset"}, {2, "Get Preset"}, {3, "Go Home"}
+};
+
+const uvc_xu_control_mapping kLogitechCmdMapping = {
+  V4L2_CID_PANTILT_CMD,
+  "Pan/Tilt Go",
+  UVC_GUID_LOGITECH_CC3000E_MOTORS,
+  LOGITECH_MOTORCONTROL_PANTILT_CMD,
+  8,
+  0,
+  V4L2_CTRL_TYPE_MENU,
+  UVC_CTRL_DATA_TYPE_ENUM,
+  const_cast<uvc_menu_info*>(&kLogitechCmdMenu[0]),
+  arraysize(kLogitechCmdMenu),
+};
+}  // namespace
+
+namespace extensions {
+
+V4L2Webcam::V4L2Webcam(const std::string& device_id) : device_id_(device_id) {
+}
+
+V4L2Webcam::~V4L2Webcam() {
+}
+
+bool V4L2Webcam::Open() {
+  fd_.reset(HANDLE_EINTR(open(device_id_.c_str(), 0)));
+  return fd_.is_valid();
+}
+
+bool V4L2Webcam::EnsureLogitechCommandsMapped() {
+  int res =
+      HANDLE_EINTR(ioctl(fd_.get(), UVCIOC_CTRL_MAP, &kLogitechCmdMapping));
+  // If mapping is successful or it's already mapped, this is a Logitech
+  // camera.
+  // NOTE: On success, occasionally EFAULT is returned.  On a real error,
+  // ENOMEM, EPERM, EINVAL, or EOVERFLOW should be returned.
+  return res >= 0 || errno == EEXIST || errno == EFAULT;
+}
+
+bool V4L2Webcam::SetWebcamParameter(int fd, uint32_t control_id, int value) {
+  struct v4l2_control v4l2_ctrl = {control_id, value};
+  int res = HANDLE_EINTR(ioctl(fd, VIDIOC_S_CTRL, &v4l2_ctrl)) >= 0;
+  return res >= 0;
+}
+
+bool V4L2Webcam::GetWebcamParameter(int fd, uint32_t control_id, int* value) {
+  struct v4l2_control v4l2_ctrl = {control_id};
+
+  if (HANDLE_EINTR(ioctl(fd, VIDIOC_G_CTRL, &v4l2_ctrl)))
+    return false;
+
+  *value = v4l2_ctrl.value;
+  return true;
+}
+
+void V4L2Webcam::Reset(bool pan, bool tilt, bool zoom) {
+  if (pan || tilt) {
+    if (EnsureLogitechCommandsMapped()) {
+      SetWebcamParameter(fd_.get(), V4L2_CID_PANTILT_CMD,
+                         kLogitechMenuIndexGoHome);
+    } else {
+      if (pan) {
+        struct v4l2_control v4l2_ctrl = {V4L2_CID_PAN_RESET};
+        HANDLE_EINTR(ioctl(fd_.get(), VIDIOC_S_CTRL, &v4l2_ctrl));
+      }
+
+      if (tilt) {
+        struct v4l2_control v4l2_ctrl = {V4L2_CID_TILT_RESET};
+        HANDLE_EINTR(ioctl(fd_.get(), VIDIOC_S_CTRL, &v4l2_ctrl));
+      }
+    }
+  }
+
+  if (zoom) {
+    const int kDefaultZoom = 100;
+    SetWebcamParameter(fd_.get(), V4L2_CID_ZOOM_ABSOLUTE, kDefaultZoom);
+  }
+}
+
+bool V4L2Webcam::GetPan(int* value) {
+  return GetWebcamParameter(fd_.get(), V4L2_CID_PAN_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::GetTilt(int* value) {
+  return GetWebcamParameter(fd_.get(), V4L2_CID_TILT_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::GetZoom(int* value) {
+  return GetWebcamParameter(fd_.get(), V4L2_CID_ZOOM_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::SetPan(int value) {
+  return SetWebcamParameter(fd_.get(), V4L2_CID_PAN_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::SetTilt(int value) {
+  return SetWebcamParameter(fd_.get(), V4L2_CID_TILT_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::SetZoom(int value) {
+  return SetWebcamParameter(fd_.get(), V4L2_CID_ZOOM_ABSOLUTE, value);
+}
+
+bool V4L2Webcam::SetPanDirection(PanDirection direction) {
+  int direction_value = 0;
+  switch (direction) {
+    case PAN_STOP:
+      direction_value = 0;
+      break;
+
+    case PAN_RIGHT:
+      direction_value = 1;
+      break;
+
+    case PAN_LEFT:
+      direction_value = -1;
+      break;
+  }
+  return SetWebcamParameter(fd_.get(), V4L2_CID_PAN_SPEED, direction_value);
+}
+
+bool V4L2Webcam::SetTiltDirection(TiltDirection direction) {
+  int direction_value = 0;
+  switch (direction) {
+    case TILT_STOP:
+      direction_value = 0;
+      break;
+
+    case TILT_UP:
+      direction_value = 1;
+      break;
+
+    case TILT_DOWN:
+      direction_value = -1;
+      break;
+  }
+  return SetWebcamParameter(fd_.get(), V4L2_CID_TILT_SPEED, direction_value);
+}
+
+}  // namespace extensions