Add a new library context object.

With the introduction of a context object, library initialization and
shutdown can be performed without requiring any global state. A single
process can use multiple independent contexts without any problems. The
lack of a global state also improves the thread-safety of the library.

At the moment, the new context object is primary used to implement an
improved logging system.

include/libdivecomputer/Makefile.am

@@ -2,6 +2,7 @@ libdivecomputerdir = $(includedir)/libdivecomputer
 libdivecomputer_HEADERS = 	\
 	version.h \
 	common.h \
+	context.h \
 	utils.h \
 	buffer.h \
 	descriptor.h \

include/libdivecomputer/context.h

@@ -0,0 +1,54 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2012 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef DC_CONTEXT_H
+#define DC_CONTEXT_H
+
+#include "common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+typedef struct dc_context_t dc_context_t;
+
+typedef enum dc_loglevel_t {
+	DC_LOGLEVEL_NONE,
+	DC_LOGLEVEL_ERROR,
+	DC_LOGLEVEL_WARNING,
+	DC_LOGLEVEL_INFO,
+	DC_LOGLEVEL_DEBUG,
+	DC_LOGLEVEL_ALL
+} dc_loglevel_t;
+
+dc_status_t
+dc_context_new (dc_context_t **context);
+
+dc_status_t
+dc_context_free (dc_context_t *context);
+
+dc_status_t
+dc_context_set_loglevel (dc_context_t *context, dc_loglevel_t loglevel);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* DC_CONTEXT_H */

src/Makefile.am

@@ -13,6 +13,7 @@ libdivecomputer_la_SOURCES = \
 	version.c \
 	descriptor.c \
 	iterator-private.h iterator.c \
+	context-private.h context.c \
 	device-private.h device.c \
 	parser-private.h parser.c \
 	datetime.c \

src/context-private.h

@@ -0,0 +1,42 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2012 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef DC_CONTEXT_PRIVATE_H
+#define DC_CONTEXT_PRIVATE_H
+
+#include <libdivecomputer/context.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#define ERROR(context, ...) dc_context_log (context, DC_LOGLEVEL_ERROR, __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
+#define WARNING(context, ...) dc_context_log (context, DC_LOGLEVEL_WARNING, __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
+#define INFO(context, ...) dc_context_log (context, DC_LOGLEVEL_INFO, __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
+#define DEBUG(context, ...) dc_context_log (context, DC_LOGLEVEL_DEBUG, __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
+
+dc_status_t
+dc_context_log (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *format, ...);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* DC_CONTEXT_PRIVATE_H */

src/context.c

@@ -0,0 +1,87 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2012 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include "context-private.h"
+
+struct dc_context_t {
+	dc_loglevel_t loglevel;
+};
+
+dc_status_t
+dc_context_new (dc_context_t **out)
+{
+	dc_context_t *context = NULL;
+
+	if (out == NULL)
+		return DC_STATUS_INVALIDARGS;
+
+	context = (dc_context_t *) malloc (sizeof (dc_context_t));
+	if (context == NULL)
+		return DC_STATUS_NOMEMORY;
+
+	context->loglevel = DC_LOGLEVEL_WARNING;
+
+	*out = context;
+
+	return DC_STATUS_SUCCESS;
+}
+
+dc_status_t
+dc_context_free (dc_context_t *context)
+{
+	free (context);
+
+	return DC_STATUS_SUCCESS;
+}
+
+dc_status_t
+dc_context_set_loglevel (dc_context_t *context, dc_loglevel_t loglevel)
+{
+	if (context == NULL)
+		return DC_STATUS_INVALIDARGS;
+
+	context->loglevel = loglevel;
+
+	return DC_STATUS_SUCCESS;
+}
+
+dc_status_t
+dc_context_log (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *format, ...)
+{
+	va_list ap;
+
+	if (context == NULL)
+		return DC_STATUS_INVALIDARGS;
+
+	if (loglevel > context->loglevel)
+		return DC_STATUS_SUCCESS;
+
+	va_start (ap, format);
+	vfprintf (stderr, format, ap);
+	va_end (ap);
+
+	return DC_STATUS_SUCCESS;
+}

src/libdivecomputer.symbols

@@ -17,6 +17,10 @@ dc_datetime_localtime
 dc_datetime_gmtime
 dc_datetime_mktime
 
+dc_context_new
+dc_context_free
+dc_context_set_loglevel
+
 dc_iterator_next
 dc_iterator_free