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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2018-12-19 02:21:28 +0200
committerNiklas Söderlund <niklas.soderlund@ragnatech.se>2019-02-01 08:11:33 +0100
commitff96eb2ebb714cef37de8e2ff19c3e56ba8bc91b (patch)
tree88394144d270860360bf807934a4e7aa52966916
parent51d442d5a1c1839bb538aeca35a9451e2d325200 (diff)
libcamera: camera: Add acquire() and release()
Exclusive access must be obtained before performing operations that change the device state. Define an internal flag to track ownership and provide a means of protecting functions that change device configuration. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
-rw-r--r--include/libcamera/camera.h5
-rw-r--r--src/libcamera/camera.cpp39
2 files changed, 43 insertions, 1 deletions
diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 5ad8a09f..a2635402 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -29,6 +29,9 @@ public:
Signal<Camera *> disconnected;
+ int acquire();
+ void release();
+
private:
Camera(PipelineHandler *pipe, const std::string &name);
~Camera();
@@ -38,6 +41,8 @@ private:
std::shared_ptr<PipelineHandler> pipe_;
std::string name_;
+
+ bool acquired_;
};
} /* namespace libcamera */
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 9cec2892..500976b2 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -102,12 +102,14 @@ const std::string &Camera::name() const
*/
Camera::Camera(PipelineHandler *pipe, const std::string &name)
- : pipe_(pipe->shared_from_this()), name_(name)
+ : pipe_(pipe->shared_from_this()), name_(name), acquired_(false)
{
}
Camera::~Camera()
{
+ if (acquired_)
+ LOG(Camera, Error) << "Removing camera while still in use";
}
/**
@@ -127,4 +129,39 @@ void Camera::disconnect()
disconnected.emit(this);
}
+/**
+ * \brief Acquire the camera device for exclusive access
+ *
+ * After opening the device with open(), exclusive access must be obtained
+ * before performing operations that change the device state. This function is
+ * not blocking, if the device has already been acquired (by the same or another
+ * process) the -EBUSY error code is returned.
+ *
+ * Once exclusive access isn't needed anymore, the device should be released
+ * with a call to the release() function.
+ *
+ * \todo Implement exclusive access across processes.
+ *
+ * \return 0 on success or a negative error code on error.
+ */
+int Camera::acquire()
+{
+ if (acquired_)
+ return -EBUSY;
+
+ acquired_ = true;
+ return 0;
+}
+
+/**
+ * \brief Release exclusive access to the camera device
+ *
+ * Releasing the camera device allows other users to acquire exclusive access
+ * with the acquire() function.
+ */
+void Camera::release()
+{
+ acquired_ = false;
+}
+
} /* namespace libcamera */