[libcamera-devel] [PATCH v2 1/3] cam: Add a parser for capture scripts
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Fri May 20 18:52:32 CEST 2022
From: Jacopo Mondi <jacopo at jmondi.org>
Add a parser class to the cam test application to control the capture
operations through a yaml script.
The capture script currently allow to specify a list of controls and
their associated values to be applied per-frame.
Also add a trivial capture script example to showcase the intended
script structure.
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
Changes since v1:
- Add SPDX license identifier to capture-script.yaml
- Drop gcc 7 support as libcamera requires gcc 8 or newer
- Make scriptPath_ a local variable in CaptureScript constructor
- Drop file check as we want to accept symlinks too
- Pass const reference to fileName to CaptureScript constructor
- Avoid manual deletes of tokens
- Simplify and improve error message handling
- Print line and column number in error message
- Simplify handling of key/value parsing
- Simplify parser deletion
- Don't consume last tokens as that's not needed.
- Simplify CaptureScript::unpackFailure()
- Switch to the simpler event API
- Typo fixes
---
src/cam/capture-script.yaml | 46 +++++
src/cam/capture_script.cpp | 334 ++++++++++++++++++++++++++++++++++++
src/cam/capture_script.h | 60 +++++++
src/cam/meson.build | 2 +
4 files changed, 442 insertions(+)
create mode 100644 src/cam/capture-script.yaml
create mode 100644 src/cam/capture_script.cpp
create mode 100644 src/cam/capture_script.h
diff --git a/src/cam/capture-script.yaml b/src/cam/capture-script.yaml
new file mode 100644
index 000000000000..6a749bc60cf7
--- /dev/null
+++ b/src/cam/capture-script.yaml
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: CC0-1.0
+
+# Capture script example
+#
+# A capture script allows to associate a list of controls and their values
+# to frame numbers.
+
+# \todo Formally define the capture script structure with a schema
+
+# Notes:
+# - Controls have to be specified by name, as defined in the
+# libcamera::controls:: enumeration
+# - Controls not supported by the camera currently operated are ignored
+# - Frame numbers shall be monotonically incrementing, gaps are allowed
+
+# Example:
+frames:
+ - 1:
+ Brightness: 0.0
+
+ - 40:
+ Brightness: 0.2
+
+ - 80:
+ Brightness: 0.4
+
+ - 120:
+ Brightness: 0.8
+
+ - 160:
+ Brightness: 0.4
+
+ - 200:
+ Brightness: 0.2
+
+ - 240:
+ Brightness: 0.0
+
+ - 280:
+ Brightness: -0.2
+
+ - 300:
+ Brightness: -0.4
+
+ - 340:
+ Brightness: -0.8
diff --git a/src/cam/capture_script.cpp b/src/cam/capture_script.cpp
new file mode 100644
index 000000000000..8e9120321a25
--- /dev/null
+++ b/src/cam/capture_script.cpp
@@ -0,0 +1,334 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * capture_script.cpp - Capture session configuration script
+ */
+
+#include "capture_script.h"
+
+#include <iostream>
+#include <stdio.h>
+#include <stdlib.h>
+
+using namespace libcamera;
+
+CaptureScript::CaptureScript(std::shared_ptr<Camera> camera,
+ const std::string &fileName)
+ : camera_(camera), valid_(false)
+{
+ FILE *fh = fopen(fileName.c_str(), "r");
+ if (!fh) {
+ int ret = -errno;
+ std::cerr << "Failed to open capture script " << fileName
+ << ": " << strerror(-ret) << std::endl;
+ return;
+ }
+
+ /*
+ * Map the camera's controls to their name so that they can be
+ * easily identified when parsing the script file.
+ */
+ for (const auto &[control, info] : camera_->controls())
+ controls_[control->name()] = control;
+
+ int ret = parseScript(fh);
+ fclose(fh);
+ if (ret)
+ return;
+
+ valid_ = true;
+}
+
+/* Retrieve the control list associated with a frame number. */
+const ControlList &CaptureScript::frameControls(unsigned int frame)
+{
+ static ControlList controls{};
+
+ auto it = frameControls_.find(frame);
+ if (it == frameControls_.end())
+ return controls;
+
+ return it->second;
+}
+
+CaptureScript::EventPtr CaptureScript::nextEvent(yaml_event_type_t expectedType)
+{
+ EventPtr event(new yaml_event_t);
+
+ if (!yaml_parser_parse(&parser_, event.get()))
+ return nullptr;
+
+ if (expectedType != YAML_NO_EVENT && !checkEvent(event, expectedType))
+ return nullptr;
+
+ return event;
+}
+
+bool CaptureScript::checkEvent(const EventPtr &event, yaml_event_type_t expectedType) const
+{
+ if (event->type != expectedType) {
+ std::cerr << "Capture script error on line " << event->start_mark.line
+ << " column " << event->start_mark.column << ": "
+ << "Expected " << eventTypeName(expectedType)
+ << " event, got " << eventTypeName(event->type)
+ << std::endl;
+ return false;
+ }
+
+ return true;
+}
+
+std::string CaptureScript::eventScalarValue(const EventPtr &event)
+{
+ return std::string(reinterpret_cast<char *>(event->data.scalar.value),
+ event->data.scalar.length);
+}
+
+std::string CaptureScript::eventTypeName(yaml_event_type_t type)
+{
+ static const std::map<yaml_event_type_t, std::string> typeNames = {
+ { YAML_STREAM_START_EVENT, "stream-start" },
+ { YAML_STREAM_END_EVENT, "stream-end" },
+ { YAML_DOCUMENT_START_EVENT, "document-start" },
+ { YAML_DOCUMENT_END_EVENT, "document-end" },
+ { YAML_ALIAS_EVENT, "alias" },
+ { YAML_SCALAR_EVENT, "scalar" },
+ { YAML_SEQUENCE_START_EVENT, "sequence-start" },
+ { YAML_SEQUENCE_END_EVENT, "sequence-end" },
+ { YAML_MAPPING_START_EVENT, "mapping-start" },
+ { YAML_MAPPING_END_EVENT, "mapping-end" },
+ };
+
+ auto it = typeNames.find(type);
+ if (it == typeNames.end())
+ return "[type " + std::to_string(type) + "]";
+
+ return it->second;
+}
+
+int CaptureScript::parseScript(FILE *script)
+{
+ int ret = yaml_parser_initialize(&parser_);
+ if (!ret) {
+ std::cerr << "Failed to initialize yaml parser" << std::endl;
+ return ret;
+ }
+
+ /* Delete the parser upon function exit. */
+ struct ParserDeleter {
+ ParserDeleter(yaml_parser_t *parser) : parser_(parser) { }
+ ~ParserDeleter() { yaml_parser_delete(parser_); }
+ yaml_parser_t *parser_;
+ } deleter(&parser_);
+
+ yaml_parser_set_input_file(&parser_, script);
+
+ EventPtr event = nextEvent(YAML_STREAM_START_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ event = nextEvent(YAML_DOCUMENT_START_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ event = nextEvent(YAML_MAPPING_START_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ while (1) {
+ event = nextEvent();
+ if (!event)
+ return -EINVAL;
+
+ if (event->type == YAML_MAPPING_END_EVENT)
+ return 0;
+
+ if (!checkEvent(event, YAML_SCALAR_EVENT))
+ return -EINVAL;
+
+ std::string section = eventScalarValue(event);
+
+ if (section == "frames") {
+ parseFrames();
+ } else {
+ std::cerr << "Unsupported section '" << section << "'"
+ << std::endl;
+ return -EINVAL;
+ }
+ }
+}
+
+int CaptureScript::parseFrames()
+{
+ EventPtr event = nextEvent(YAML_SEQUENCE_START_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ while (1) {
+ event = nextEvent();
+ if (!event)
+ return -EINVAL;
+
+ if (event->type == YAML_SEQUENCE_END_EVENT)
+ return 0;
+
+ int ret = parseFrame(std::move(event));
+ if (ret)
+ return ret;
+ }
+}
+
+int CaptureScript::parseFrame(EventPtr event)
+{
+ if (!checkEvent(event, YAML_MAPPING_START_EVENT))
+ return -EINVAL;
+
+ std::string key = parseScalar();
+ if (key.empty())
+ return -EINVAL;
+
+ unsigned int frameId = atoi(key.c_str());
+
+ event = nextEvent(YAML_MAPPING_START_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ ControlList controls{};
+
+ while (1) {
+ event = nextEvent();
+ if (!event)
+ return -EINVAL;
+
+ if (event->type == YAML_MAPPING_END_EVENT)
+ break;
+
+ int ret = parseControl(std::move(event), controls);
+ if (ret)
+ return ret;
+ }
+
+ frameControls_[frameId] = std::move(controls);
+
+ event = nextEvent(YAML_MAPPING_END_EVENT);
+ if (!event)
+ return -EINVAL;
+
+ return 0;
+}
+
+int CaptureScript::parseControl(EventPtr event, ControlList &controls)
+{
+ /* We expect a value after a key. */
+ std::string name = eventScalarValue(event);
+ if (name.empty())
+ return -EINVAL;
+
+ /* If the camera does not support the control just ignore it. */
+ auto it = controls_.find(name);
+ if (it == controls_.end()) {
+ std::cerr << "Unsupported control '" << name << "'" << std::endl;
+ return -EINVAL;
+ }
+
+ std::string value = parseScalar();
+ if (value.empty())
+ return -EINVAL;
+
+ const ControlId *controlId = it->second;
+ ControlValue val = unpackControl(controlId, value);
+ controls.set(controlId->id(), val);
+
+ return 0;
+}
+
+std::string CaptureScript::parseScalar()
+{
+ EventPtr event = nextEvent(YAML_SCALAR_EVENT);
+ if (!event)
+ return "";
+
+ return eventScalarValue(event);
+}
+
+void CaptureScript::unpackFailure(const ControlId *id, const std::string &repr)
+{
+ static const std::map<unsigned int, const char *> typeNames = {
+ { ControlTypeNone, "none" },
+ { ControlTypeBool, "bool" },
+ { ControlTypeByte, "byte" },
+ { ControlTypeInteger32, "int32" },
+ { ControlTypeInteger64, "int64" },
+ { ControlTypeFloat, "float" },
+ { ControlTypeString, "string" },
+ { ControlTypeRectangle, "Rectangle" },
+ { ControlTypeSize, "Size" },
+ };
+
+ const char *typeName;
+ auto it = typeNames.find(id->type());
+ if (it != typeNames.end())
+ typeName = it->second;
+ else
+ typeName = "unknown";
+
+ std::cerr << "Unsupported control '" << repr << "' for "
+ << typeName << " control " << id->name() << std::endl;
+}
+
+ControlValue CaptureScript::unpackControl(const ControlId *id,
+ const std::string &repr)
+{
+ ControlValue value{};
+
+ switch (id->type()) {
+ case ControlTypeNone:
+ break;
+ case ControlTypeBool: {
+ bool val;
+
+ if (repr == "true") {
+ val = true;
+ } else if (repr == "false") {
+ val = false;
+ } else {
+ unpackFailure(id, repr);
+ return value;
+ }
+
+ value.set<bool>(val);
+ break;
+ }
+ case ControlTypeByte: {
+ uint8_t val = strtol(repr.c_str(), NULL, 10);
+ value.set<uint8_t>(val);
+ break;
+ }
+ case ControlTypeInteger32: {
+ int32_t val = strtol(repr.c_str(), NULL, 10);
+ value.set<int32_t>(val);
+ break;
+ }
+ case ControlTypeInteger64: {
+ int64_t val = strtoll(repr.c_str(), NULL, 10);
+ value.set<int64_t>(val);
+ break;
+ }
+ case ControlTypeFloat: {
+ float val = strtof(repr.c_str(), NULL);
+ value.set<float>(val);
+ break;
+ }
+ case ControlTypeString: {
+ value.set<std::string>(repr);
+ break;
+ }
+ case ControlTypeRectangle:
+ /* \todo Parse rectangles. */
+ break;
+ case ControlTypeSize:
+ /* \todo Parse Sizes. */
+ break;
+ }
+
+ return value;
+}
diff --git a/src/cam/capture_script.h b/src/cam/capture_script.h
new file mode 100644
index 000000000000..44368f63f34c
--- /dev/null
+++ b/src/cam/capture_script.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * capture_script.h - Capture session configuration script
+ */
+
+#pragma once
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include <libcamera/camera.h>
+#include <libcamera/controls.h>
+
+#include <yaml.h>
+
+class CaptureScript
+{
+public:
+ CaptureScript(std::shared_ptr<libcamera::Camera> camera,
+ const std::string &fileName);
+
+ bool valid() const { return valid_; }
+
+ const libcamera::ControlList &frameControls(unsigned int frame);
+
+private:
+ struct EventDeleter {
+ void operator()(yaml_event_t *event) const
+ {
+ yaml_event_delete(event);
+ delete event;
+ }
+ };
+ using EventPtr = std::unique_ptr<yaml_event_t, EventDeleter>;
+
+ std::map<std::string, const libcamera::ControlId *> controls_;
+ std::map<unsigned int, libcamera::ControlList> frameControls_;
+ std::shared_ptr<libcamera::Camera> camera_;
+ yaml_parser_t parser_;
+ bool valid_;
+
+ EventPtr nextEvent(yaml_event_type_t expectedType = YAML_NO_EVENT);
+ bool checkEvent(const EventPtr &event, yaml_event_type_t expectedType) const;
+ static std::string eventScalarValue(const EventPtr &event);
+ static std::string eventTypeName(yaml_event_type_t type);
+
+ int parseScript(FILE *script);
+
+ int parseFrames();
+ int parseFrame(EventPtr event);
+ int parseControl(EventPtr event, libcamera::ControlList &controls);
+
+ std::string parseScalar();
+
+ void unpackFailure(const libcamera::ControlId *id,
+ const std::string &repr);
+ libcamera::ControlValue unpackControl(const libcamera::ControlId *id,
+ const std::string &repr);
+};
diff --git a/src/cam/meson.build b/src/cam/meson.build
index 5bab8c9e331b..c47a85592478 100644
--- a/src/cam/meson.build
+++ b/src/cam/meson.build
@@ -11,6 +11,7 @@ cam_enabled = true
cam_sources = files([
'camera_session.cpp',
+ 'capture_script.cpp',
'event_loop.cpp',
'file_sink.cpp',
'frame_sink.cpp',
@@ -38,6 +39,7 @@ cam = executable('cam', cam_sources,
libcamera_public,
libdrm,
libevent,
+ libyaml,
],
cpp_args : cam_cpp_args,
install : true)
--
Regards,
Laurent Pinchart
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