[PATCH v3] qcam: Automatically select the camera if only one is available

[Stanislaw Gruszka]

When only a single camera is available, showing the camera selection
dialog is unnecessary. It's better to automatically select the available
camera without prompting the user for input.

Co-developed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
---
v2:
- Avoid cm_->cameras().size() vs cm_->cameras()[0] race condition
  using custom loop.
- Update in code comment
v3: 
- Avoid TOCTOU race using shared_ptr vector copy
- Use Laurent comment wording

 src/apps/qcam/main_window.cpp | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/apps/qcam/main_window.cpp b/src/apps/qcam/main_window.cpp
index 5144c6b3..de487672 100644
--- a/src/apps/qcam/main_window.cpp
+++ b/src/apps/qcam/main_window.cpp
@@ -298,13 +298,19 @@ int MainWindow::openCamera()
 	std::string cameraName;
 
 	/*
-	 * Use the camera specified on the command line, if any, or display the
-	 * camera selection dialog box otherwise.
+	 * If a camera is specified on the command line, get it. Otherwise, if
+	 * only one camera is available, pick it automatically, else, display
+	 * the selector dialog box.
 	 */
-	if (options_.isSet(OptCamera))
+	if (options_.isSet(OptCamera)) {
 		cameraName = static_cast<std::string>(options_[OptCamera]);
-	else
-		cameraName = chooseCamera();
+	} else {
+		std::vector<std::shared_ptr<Camera>> cameras = cm_->cameras();
+		if (cameras.size() == 1)
+			cameraName = cameras[0]->id();
+		else
+			cameraName = chooseCamera();
+	}
 
 	if (cameraName == "")
 		return -EINVAL;
-- 
2.43.0