lcameraDev: Add session mgr lib for libcamera device binding

commonLibs/lcameraDev/selectorResolve.cpp

@@ -0,0 +1,171 @@
+#include <selectorResolve.h>
+#include <algorithm>
+#include <cctype>
+#include <optional>
+#include <sstream>
+#include <stdexcept>
+
+namespace lcamera_dev {
+
+namespace {
+
+std::string toLowerAscii(const std::string& text)
+{
+	std::string lowered = text;
+	for (char& ch : lowered) {
+		ch = static_cast<char>(std::tolower(static_cast<unsigned char>(ch)));
+	}
+	return lowered;
+}
+
+bool recordMatchesCriterion(
+	const CameraIdentityRecord& record, const SelectorCriterion& criterion)
+{
+	switch (criterion.kind)
+	{
+	case SelectorCriterionKind::LibcameraId:
+		return record.id == criterion.value;
+
+	case SelectorCriterionKind::Index:
+		return false;
+
+	case SelectorCriterionKind::Model:
+		return record.model == criterion.value;
+
+	case SelectorCriterionKind::ModelSubstr:
+		return record.model.find(criterion.value) != std::string::npos;
+
+	case SelectorCriterionKind::Location:
+		return toLowerAscii(record.locationLabel)
+			== toLowerAscii(criterion.value);
+	}
+
+	return false;
+}
+
+int parseIndexCriterion(const SelectorCriterion& criterion)
+{
+	try {
+		return std::stoi(criterion.value);
+	}
+	catch (const std::exception&) {
+		throw std::runtime_error("Invalid index: value in deviceSelector");
+	}
+}
+
+} // namespace
+
+std::string formatCameraListForDiagnostics(
+	const std::vector<CameraIdentityRecord>& records)
+{
+	std::ostringstream result;
+	result << "Known cameras:\n";
+
+	for (size_t i = 0; i < records.size(); ++i)
+	{
+		const CameraIdentityRecord& record = records[i];
+		result << "  [" << i << "] id=" << record.id;
+		if (!record.model.empty()) {
+			result << " model=" << record.model;
+		}
+		if (!record.locationLabel.empty()) {
+			result << " location=" << record.locationLabel;
+		}
+		result << '\n';
+	}
+
+	return result.str();
+}
+
+CameraIdentityRecord resolveSelectorAgainstRecords(
+	const std::vector<SelectorCriterion>& criteria,
+	const std::vector<CameraIdentityRecord>& records)
+{
+	std::optional<int> indexCriterion;
+	for (const SelectorCriterion& criterion : criteria)
+	{
+		if (criterion.kind != SelectorCriterionKind::Index) {
+			continue;
+		}
+
+		const int index = parseIndexCriterion(criterion);
+		if (index < 0
+			|| static_cast<size_t>(index) >= records.size())
+		{
+			throw std::runtime_error("index: selector out of range");
+		}
+
+		indexCriterion = index;
+	}
+
+	std::vector<const CameraIdentityRecord*> matches;
+	matches.reserve(records.size());
+
+	for (const CameraIdentityRecord& record : records)
+	{
+		bool matchesAll = true;
+		for (const SelectorCriterion& criterion : criteria)
+		{
+			if (criterion.kind == SelectorCriterionKind::Index) {
+				continue;
+			}
+
+			if (!recordMatchesCriterion(record, criterion))
+			{
+				matchesAll = false;
+				break;
+			}
+		}
+
+		if (!matchesAll) {
+			continue;
+		}
+
+		matches.push_back(&record);
+	}
+
+	if (indexCriterion.has_value())
+	{
+		const CameraIdentityRecord& indexedRecord =
+			records.at(static_cast<size_t>(*indexCriterion));
+
+		auto it = std::find_if(
+			matches.begin(), matches.end(),
+			[&indexedRecord](const CameraIdentityRecord* candidate) {
+				return candidate->id == indexedRecord.id;
+			});
+
+		if (it == matches.end())
+		{
+			throw std::runtime_error(
+				"index: criterion conflicts with other selector clauses");
+		}
+
+		if (matches.size() > 1)
+		{
+			throw std::runtime_error(
+				"Ambiguous deviceSelector: multiple cameras match\n"
+				+ formatCameraListForDiagnostics(records));
+		}
+
+		return indexedRecord;
+	}
+
+	if (matches.empty())
+	{
+		throw std::runtime_error(
+			"No camera matches deviceSelector\n"
+			+ formatCameraListForDiagnostics(records));
+	}
+
+	if (matches.size() > 1)
+	{
+		throw std::runtime_error(
+			"Ambiguous deviceSelector: multiple cameras match\n"
+			+ formatCameraListForDiagnostics(records));
+	}
+
+	return *matches.front();
+}
+
+} // namespace lcamera_dev