[PATCH v2 2/7] libcamera: Add a DebugMetadata helper
Stefan Klug
stefan.klug at ideasonboard.com
Mon Oct 7 11:54:06 CEST 2024
Debug metadata often occurs in places where the metadata control list is
not available e.g. in queueRequest() or processStatsBuffer() or even in
a class far away from the metadata handling code. It is therefore
difficult to add debug metadata without adding lots of boilerplate
code. This can be mitigated by recording the metadata and forwarding it
to the metadata control list when it becomes available. To solve the
issue of code that is far away from the metadata context, add a chaining
mechanism to allow loose coupling at runtime.
Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
---
Changes in v2:
- Replace assignments of ControlList by a moveEntries function
- Replace assignUpstream by setParent
- Improve documentation
---
include/libcamera/internal/debug_controls.h | 46 +++++++
include/libcamera/internal/meson.build | 1 +
src/libcamera/control_ids_core.yaml | 5 +
src/libcamera/control_ids_debug.yaml | 3 +-
src/libcamera/debug_controls.cpp | 145 ++++++++++++++++++++
src/libcamera/meson.build | 1 +
6 files changed, 199 insertions(+), 2 deletions(-)
create mode 100644 include/libcamera/internal/debug_controls.h
create mode 100644 src/libcamera/debug_controls.cpp
diff --git a/include/libcamera/internal/debug_controls.h b/include/libcamera/internal/debug_controls.h
new file mode 100644
index 000000000000..00457d60b1a2
--- /dev/null
+++ b/include/libcamera/internal/debug_controls.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Google Inc.
+ *
+ * Debug metadata helpers
+ */
+
+#pragma once
+
+#include <libcamera/control_ids.h>
+
+namespace libcamera {
+
+class DebugMetadata
+{
+public:
+ DebugMetadata() = default;
+
+ void checkForEnable(const ControlList &controls);
+ void enable(bool enable = true);
+ void setParent(DebugMetadata *parent);
+ void moveEntries(ControlList &list);
+
+ template<typename T, typename V>
+ void set(const Control<T> &ctrl, const V &value)
+ {
+ if (parent_) {
+ parent_->set<T, V>(ctrl, value);
+ return;
+ }
+
+ if (!enabled_)
+ return;
+
+ cache_.set<T, V>(ctrl, value);
+ }
+
+ void set(unsigned int id, const ControlValue &value);
+
+private:
+ bool enabled_ = false;
+ DebugMetadata *parent_ = nullptr;
+ ControlList cache_;
+};
+
+} /* namespace libcamera */
diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
index 1c5eef9cab80..1dddcd50c90b 100644
--- a/include/libcamera/internal/meson.build
+++ b/include/libcamera/internal/meson.build
@@ -14,6 +14,7 @@ libcamera_internal_headers = files([
'control_serializer.h',
'control_validator.h',
'converter.h',
+ 'debug_controls.h',
'delayed_controls.h',
'device_enumerator.h',
'device_enumerator_sysfs.h',
diff --git a/src/libcamera/control_ids_core.yaml b/src/libcamera/control_ids_core.yaml
index 1b1bd9507d25..d34a2d068b60 100644
--- a/src/libcamera/control_ids_core.yaml
+++ b/src/libcamera/control_ids_core.yaml
@@ -968,4 +968,9 @@ controls:
The default gamma value must be 2.2 which closely mimics sRGB gamma.
Note that this is camera gamma, so it is applied as 1.0/gamma.
+ - DebugMetadataEnable:
+ type: bool
+ description: |
+ Enable or disable the debug metadata.
+
...
diff --git a/src/libcamera/control_ids_debug.yaml b/src/libcamera/control_ids_debug.yaml
index 62f742c58129..797532712099 100644
--- a/src/libcamera/control_ids_debug.yaml
+++ b/src/libcamera/control_ids_debug.yaml
@@ -3,5 +3,4 @@
%YAML 1.1
---
vendor: debug
-controls:
-
+controls: []
diff --git a/src/libcamera/debug_controls.cpp b/src/libcamera/debug_controls.cpp
new file mode 100644
index 000000000000..84157aca5a74
--- /dev/null
+++ b/src/libcamera/debug_controls.cpp
@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Google Inc.
+ *
+ * Helper to easily record debug metadata inside libcamera.
+ */
+
+#include "libcamera/internal/debug_controls.h"
+
+#include <libcamera/base/log.h>
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(DebugControls)
+
+/**
+ * \file debug_controls.h
+ * \brief Helper to easily record debug metadata inside libcamera
+ */
+
+/**
+ * \class DebugMetadata
+ * \brief Helper to record metadata for later use
+ *
+ * When one wants to record debug metadata, the metadata list is often not
+ * directly available (either because we are inside process() of an IPA or
+ * because we are in a closed module). This class allows to record the data and
+ * at a later point in time forward it either to another DebugMetadata instance
+ * or to a ControlList.
+ */
+
+/**
+ * \fn DebugMetadata::checkForEnable
+ * \brief Check for DebugMetadataEnable in the supplied ControlList
+ * \param[in] controls The supplied ControlList
+ *
+ * Looks for controls::DebugMetadataEnable and enables or disables debug
+ * metadata handling accordingly.
+ */
+void DebugMetadata::checkForEnable(const ControlList &controls)
+{
+ const auto &ctrl = controls.get(controls::DebugMetadataEnable);
+ if (ctrl)
+ enable(*ctrl);
+}
+
+/**
+ * \fn DebugMetadata::enable
+ * \brief Enables or disabled metadata handling
+ * \param[in] enable The enable state
+ *
+ * Enables or disables metadata handling according to \a enable. When \a enable
+ * is true, all calls to set() get cached and can later be retrieved using \a
+ * DebugMetadata::moveEntries(). When \a enable is false, the cache gets cleared
+ * and no further metadata is recorded.
+ *
+ * Forwarding to a parent is independent of the enabled state.
+ */
+void DebugMetadata::enable(bool enable)
+{
+ enabled_ = enable;
+ if (!enabled_)
+ cache_.clear();
+}
+
+/**
+ * \fn DebugMetadata::setParent
+ * \brief Assign a parent metadata handler
+ * \param[in] parent Pointer to the parent handler
+ *
+ * When a \a parent gets set, all further calls to DebugMetadata::set are
+ * forwarded to that instance. It is not allowed to enable a DebugMetadata
+ * object, log entries to it and later set the parent. This is done to keep a
+ * path open for switching to tracing infrastructure later. For tracing one
+ * would need some kind of "context" identifier that needs to be available on
+ * set() time. The parent can be treated as such. The top level object
+ * (the one where enable() get's called) lives in a place where that information
+ * is also available.
+ *
+ * The parent can be reset by passing a nullptr.
+ */
+void DebugMetadata::setParent(DebugMetadata *parent)
+{
+ parent_ = parent;
+
+ if (!parent_)
+ return;
+
+ if (!cache_.empty())
+ LOG(DebugControls, Error)
+ << "Controls were recorded before setting a parent."
+ << " These are dropped.";
+
+ cache_.clear();
+}
+
+/**
+ * \fn DebugMetadata::moveEntries
+ * \brief Move all cached entries into a list
+ * \param[in] list The list
+ *
+ * Moves all entries into the list specified by \a list. Duplicate entries in
+ * \a list get overwritten.
+ */
+void DebugMetadata::moveEntries(ControlList &list)
+{
+ list.merge(std::move(cache_), ControlList::MergePolicy::OverwriteExisting);
+ cache_.clear();
+}
+
+/**
+ * \fn DebugMetadata::set(const Control<T> &ctrl, const V &value)
+ * \brief Set a value
+ * \param[in] ctrl The ctrl to set
+ * \param[in] value The control value
+ *
+ * Sets the debug metadata for \a ctrl to value \a value. If a parent is set,
+ * the value gets passed there unconditionally. Otherwise it gets cached if the
+ * instance is enabled or dropped silently when disabled.
+ */
+
+/**
+ * \fn DebugMetadata::set(unsigned int id, const ControlValue &value)
+ * \brief Set a value
+ * \param[in] id The id of the control
+ * \param[in] value The control value
+ *
+ * Sets the debug metadata for \a id to value \a value. If a parent is set,
+ * the value gets passed there unconditionally. Otherwise it gets cached if the
+ * instance is enabled or dropped silently when disabled.
+ */
+void DebugMetadata::set(unsigned int id, const ControlValue &value)
+{
+ if (parent_) {
+ parent_->set(id, value);
+ return;
+ }
+
+ if (!enabled_)
+ return;
+
+ cache_.set(id, value);
+}
+
+} /* namespace libcamera */
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index aa9ab0291854..f7b5ee8dcc34 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -25,6 +25,7 @@ libcamera_internal_sources = files([
'control_validator.cpp',
'converter.cpp',
'delayed_controls.cpp',
+ 'debug_controls.cpp',
'device_enumerator.cpp',
'device_enumerator_sysfs.cpp',
'dma_buf_allocator.cpp',
--
2.43.0
More information about the libcamera-devel
mailing list