[libcamera-devel] [PATCH 1/2] libcamera: logging: add logging API for applications

[Paul Elder]

Currently the log file and the log level can only be set via environment
variables, but applications may also want to set the log file and the
log level at run time. Provide an API for this.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
---
 include/libcamera/logging.h   | 17 +++++++++++++++++
 include/libcamera/meson.build |  1 +
 src/libcamera/log.cpp         | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+)
 create mode 100644 include/libcamera/logging.h

diff --git a/include/libcamera/logging.h b/include/libcamera/logging.h
new file mode 100644
index 0000000..47c5e49
--- /dev/null
+++ b/include/libcamera/logging.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2018, Google Inc.
+ *
+ * log.h - Logging infrastructure
+ */
+#ifndef __LIBCAMERA_LOGGING_H__
+#define __LIBCAMERA_LOGGING_H__
+
+namespace libcamera {
+
+void logSetFile(const char *file);
+void logSetLevel(const char *category, const char *level);
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_LOGGING_H__ */
diff --git a/include/libcamera/meson.build b/include/libcamera/meson.build
index 972513f..920eb5f 100644
--- a/include/libcamera/meson.build
+++ b/include/libcamera/meson.build
@@ -9,6 +9,7 @@ libcamera_api = files([
     'geometry.h',
     'ipa/ipa_interface.h',
     'ipa/ipa_module_info.h',
+    'logging.h',
     'object.h',
     'request.h',
     'signal.h',
diff --git a/src/libcamera/log.cpp b/src/libcamera/log.cpp
index 0ba276e..e322b8f 100644
--- a/src/libcamera/log.cpp
+++ b/src/libcamera/log.cpp
@@ -69,6 +69,9 @@ private:
 	void parseLogLevels();
 	static LogSeverity parseLogLevel(const std::string &level);
 
+	friend void logSetFile(const char *file);
+	friend void logSetLevel(const char *category, const char *level);
+
 	friend LogCategory;
 	void registerCategory(LogCategory *category);
 	void unregisterCategory(LogCategory *category);
@@ -80,6 +83,35 @@ private:
 	std::ostream *output_;
 };
 
+void logSetFile(const char *file)
+{
+	if (std::string(file).empty())
+		return;
+
+	Logger *logger = Logger::instance();
+	std::ofstream &file_ = logger->file_;
+	file_.close();
+	file_.open(file);
+	if (file_.good())
+		logger->output_ = &file_;
+}
+
+void logSetLevel(const char *category, const char *level)
+{
+	std::string cat(category);
+	std::string lev(level);
+
+	/* Both the category and the level must be specified. */
+	if (cat.empty() || lev.empty())
+		return;
+
+	LogSeverity severity = Logger::parseLogLevel(lev);
+	if (severity == LogInvalid)
+		return;
+
+	Logger::instance()->levels_.push_back({ cat, severity });
+}
+
 /**
  * \brief Retrieve the logger instance
  *
-- 
2.20.1