libcamera: Refactor the camera configuration storage and API

Refactor the CameraConfiguration structure to not rely on Stream
instances. This is a step towards making the camera configuration object
more powerful with configuration validation using "try" semantics.

The CameraConfiguration now exposes a simple vector-like API to access
the contained stream configurations. Both operator[]() and at() are
provided to access elements. The isEmpty() method is renamed to empty()
and the methods reordered to match the std::vector class.

As applications need access to the Stream instances associated with the
configuration entries in order to associate buffers with streams when
creating requests, expose the stream selected by the pipeline handler
through a new StreamConfiguration::stream().

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

1 files changed, 18 insertions, 17 deletions

diff --git a/src/cam/main.cpp b/src/cam/main.cpp
index d603228c..cd165bea 100644
--- a/src/cam/main.cpp
+++ b/src/cam/main.cpp
@@ -89,12 +89,9 @@ static int prepareCameraConfig(CameraConfiguration *config)
 {
 	StreamRoles roles;
 
-	streamInfo.clear();
-
 	/* If no configuration is provided assume a single video stream. */
 	if (!options.isSet(OptStream)) {
 		*config = camera->generateConfiguration({ StreamRole::VideoRecording });
-		streamInfo[config->front()] = "stream0";
 		return 0;
 	}
 
@@ -129,27 +126,20 @@ static int prepareCameraConfig(CameraConfiguration *config)
 	}
 
 	/* Apply configuration explicitly requested. */
-	CameraConfiguration::iterator it = config->begin();
+	unsigned int i = 0;
 	for (auto const &value : streamOptions) {
 		KeyValueParser::Options conf = value.toKeyValues();
-		Stream *stream = *it;
-		it++;
+		StreamConfiguration &cfg = (*config)[i++];
 
 		if (conf.isSet("width"))
-			(*config)[stream].size.width = conf["width"];
+			cfg.size.width = conf["width"];
 
 		if (conf.isSet("height"))
-			(*config)[stream].size.height = conf["height"];
+			cfg.size.height = conf["height"];
 
 		/* TODO: Translate 4CC string to ID. */
 		if (conf.isSet("pixelformat"))
-			(*config)[stream].pixelFormat = conf["pixelformat"];
-	}
-
-	unsigned int index = 0;
-	for (Stream *stream : *config) {
-		streamInfo[stream] = "stream" + std::to_string(index);
-		index++;
+			cfg.pixelFormat = conf["pixelformat"];
 	}
 
 	return 0;
@@ -216,6 +206,13 @@ static int capture()
 		return ret;
 	}
 
+	streamInfo.clear();
+
+	for (unsigned int index = 0; index < config.size(); ++index) {
+		StreamConfiguration &cfg = config[index];
+		streamInfo[cfg.stream()] = "stream" + std::to_string(index);
+	}
+
 	ret = camera->allocateBuffers();
 	if (ret) {
 		std::cerr << "Failed to allocate buffers"
@@ -227,8 +224,10 @@ static int capture()
 
 	/* Identify the stream with the least number of buffers. */
 	unsigned int nbuffers = UINT_MAX;
-	for (Stream *stream : config)
+	for (StreamConfiguration &cfg : config) {
+		Stream *stream = cfg.stream();
 		nbuffers = std::min(nbuffers, stream->bufferPool().count());
+	}
 
 	/*
 	 * TODO: make cam tool smarter to support still capture by for
@@ -245,8 +244,10 @@ static int capture()
 		}
 
 		std::map<Stream *, Buffer *> map;
-		for (Stream *stream : config)
+		for (StreamConfiguration &cfg : config) {
+			Stream *stream = cfg.stream();
 			map[stream] = &stream->bufferPool().buffers()[i];
+		}
 
 		ret = request->setBuffers(map);
 		if (ret < 0) {