[libcamera-devel] [PATCH v6 1/9] libcamera: control_serializer: Save serialized ControlInfoMap in a cache

[Paul Elder]

The ControlSerializer saves all ControlInfoMaps that it has already
(de)serialized, in order to (de)serialize ControlLists that contain the
ControlInfoMaps. Leverage this to cache ControlInfoMaps, such that the
ControlSerializer will not re-(de)serialize a ControlInfoMap that it has
previously (de)serialized.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
New in v6
---
 .../libcamera/internal/control_serializer.h   |  1 +
 src/libcamera/control_serializer.cpp          | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/libcamera/internal/control_serializer.h b/include/libcamera/internal/control_serializer.h
index 0ab29d9a..76cb3c10 100644
--- a/include/libcamera/internal/control_serializer.h
+++ b/include/libcamera/internal/control_serializer.h
@@ -33,6 +33,7 @@ public:
 	template<typename T>
 	T deserialize(ByteStreamBuffer &buffer);
 
+	bool isCached(const ControlInfoMap *infoMap);
 private:
 	static size_t binarySize(const ControlValue &value);
 	static size_t binarySize(const ControlInfo &info);
diff --git a/src/libcamera/control_serializer.cpp b/src/libcamera/control_serializer.cpp
index 258db6df..4cf1c720 100644
--- a/src/libcamera/control_serializer.cpp
+++ b/src/libcamera/control_serializer.cpp
@@ -173,6 +173,11 @@ void ControlSerializer::store(const ControlInfo &info, ByteStreamBuffer &buffer)
 int ControlSerializer::serialize(const ControlInfoMap &infoMap,
 				 ByteStreamBuffer &buffer)
 {
+	if (isCached(&infoMap)) {
+		LOG(Serializer, Info) << "Serializing ControlInfoMap from cache";
+		return 0;
+	}
+
 	/* Compute entries and data required sizes. */
 	size_t entriesSize = infoMap.size()
 			   * sizeof(struct ipa_control_info_entry);
@@ -347,6 +352,12 @@ ControlInfoMap ControlSerializer::deserialize<ControlInfoMap>(ByteStreamBuffer &
 		return {};
 	}
 
+	auto iter = infoMaps_.find(hdr->handle);
+	if (iter != infoMaps_.end()) {
+		LOG(Serializer, Info) << "Deserializing ControlInfoMap from cache";
+		return iter->second;
+	}
+
 	if (hdr->version != IPA_CONTROLS_FORMAT_VERSION) {
 		LOG(Serializer, Error)
 			<< "Unsupported controls format version "
@@ -485,4 +496,23 @@ ControlList ControlSerializer::deserialize<ControlList>(ByteStreamBuffer &buffer
 	return ctrls;
 }
 
+/**
+ * \brief Check if some ControlInfoMap is cached
+ * \param[in] infoMap The ControlInfoMap to check
+ *
+ * The ControlSerializer caches all ControlInfoMaps that it has (de)serialized.
+ * This function checks if \a infoMap is in the cache.
+ *
+ * \return True if \a infoMap is in the cache or if \a infoMap is
+ * controls::controls, false otherwise
+ */
+bool ControlSerializer::isCached(const ControlInfoMap *infoMap)
+{
+	if (!infoMap)
+		return true;
+
+	auto iter = infoMapHandles_.find(infoMap);
+	return iter != infoMapHandles_.end();
+}
+
 } /* namespace libcamera */
-- 
2.27.0