Hi
----- Original Message -----
> >
> > From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
> >
> > A log category is defined with SPICE_LOG_CATEGORY(). The macro will
> > register a structure with a constructor (and unregister it on
> > unloading with a destructor).
> >
> > spice_log_init() must be called at initialization time, to set enabled
> > categories and add the 'Spice' glib domain to G_MESSAGES_DEBUG (NB: if
> > useful, we could have other log domains automatically associated with
> > categories and enable them too).
> >
> > A category can be enabled with SPICE_DEBUG="cat_name foo*" (*? are
> > accepted glob-like wildcards). All categories are enabled with
> > SPICE_DEBUG=1 or 'all'. To list available categories, you can run the
> > program with SPICE_DEBUG=help.
> >
> > spice_log() will log the debug message using structured logging if
> > available (or fallback on regular glog). The associated Spice log in
> > the journal will have the SPICE_LOG_CATEGORY field set accordingly.
> >
> > If deemed necessary, you can also avoid expensive log computation with
> > SPICE_LOG_ENABLED() macro help.
> >
> > TODO: add tests
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
> > ---
> > common/log.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
> > common/log.h | 72
> > +++++++++++++++++++++++++++++++++++++++++++++++++++-
> > tests/test-logging.c | 1 +
> > 3 files changed, 139 insertions(+), 1 deletion(-)
> >
> > diff --git a/common/log.c b/common/log.c
> > index 6a15a30..029e279 100644
> > --- a/common/log.c
> > +++ b/common/log.c
> > @@ -18,3 +18,70 @@
> > #ifdef HAVE_CONFIG_H
> > #include <config.h>
> > #endif
> > +
> > +#include "log.h"
> > +
> > +static GSList *log_categories = NULL; /* all registered log categories */
> > +
> > +void spice_log_category_register(SpiceLogCategory *cat)
> > +{
> > + if (!g_slist_find(log_categories, cat)) {
> > + log_categories = g_slist_prepend(log_categories, cat);
> > + }
> > +}
> > +
> > +void spice_log_category_unregister(SpiceLogCategory *cat)
> > +{
> > + log_categories = g_slist_remove(log_categories, cat);
> > +}
> > +
> > +void spice_log_init(void)
> > +{
> > + bool all = false;
> > + const char *env = g_getenv("SPICE_DEBUG");
> > + const char *genv = g_getenv("G_MESSAGES_DEBUG");
> > +
> > + if (g_strcmp0(env, "help") == 0) {
>
> I agree with other people that this "help" usage is weird.
Not weird for a gnome/glib developper (G*_DEBUG).
In any case, this is going to be exposed in --spice-debug as Christophe F. suggested.
>
> > + g_printerr("SPICE_DEBUG=1 or 'all' to enable all debug\n");
> > + g_printerr("SPICE_DEBUG=\"cat1* cat2\" to enable specific
> > categories\n");
> > + g_printerr("Available Spice debug categories:\n");
> > + for (GSList *l = log_categories; l != NULL; l = g_slist_next(l)) {
> > + SpiceLogCategory *cat = l->data;
> > + g_printerr("%-20s - %s\n", cat->name, cat->desc);
> > + }
> > + return;
> > + }
> > +
> > + /* Make sure GLib default log handler will show the debug
> > + * messages. Messing with environment variables like this is
> > + * rather ugly, but done for historical reasons.
> > + */
> > + if (env && *env != '\0') {
> > + if (genv == NULL) {
> > + g_setenv("G_MESSAGES_DEBUG", G_LOG_DOMAIN, TRUE);
> > + } else if (!g_str_equal(genv, "all")) {
> > + char *new_env = g_strconcat(genv, " ", G_LOG_DOMAIN, NULL);
> > + g_setenv("G_MESSAGES_DEBUG", new_env, TRUE);
> > + g_free(new_env);
> > + }
> > + }
> > +
> > + all = g_strcmp0(env, "1") == 0 || g_strcmp0(env, "all") == 0;
> > + if (all) {
> > + for (GSList *l = log_categories; l != NULL; l = g_slist_next(l)) {
> > + SpiceLogCategory *cat = l->data;
> > + cat->enabled = true;
> > + }
> > + } else if (env) {
> > + char **cat_sel = g_strsplit(env, " ", -1);
> > + for (char **strv = cat_sel; *strv != NULL; strv++) {
> > + GPatternSpec *pat = g_pattern_spec_new(*strv);
> > + for (GSList *l = log_categories; l != NULL; l =
> > g_slist_next(l))
> > {
> > + SpiceLogCategory *cat = l->data;
> > + cat->enabled = g_pattern_match_string(pat, cat->name);
> > + }
> > + g_pattern_spec_free(pat);
> > + }
> > + g_strfreev(cat_sel);
> > + }
> > +}
> > diff --git a/common/log.h b/common/log.h
> > index b86fd08..e202563 100644
> > --- a/common/log.h
> > +++ b/common/log.h
> > @@ -28,6 +28,63 @@
> >
> > G_BEGIN_DECLS
> >
> > +typedef struct SpiceLogCategory {
> > + const char *name;
> > + const char *desc;
> > + bool enabled;
> > +} SpiceLogCategory;
> > +
> > +/* This is only useful if the category is shared in several units. */
> > +/* The code could probably be better organized instead. */
> > +#define SPICE_LOG_CATEGORY_DECLARE(Name) \
> > + extern SpiceLogCategory G_PASTE(spice_log_category_, Name);
> > +
> > +#define SPICE_LOG_CATEGORY(Name, Desc) \
> > + SpiceLogCategory G_PASTE(spice_log_category_, Name) = { \
> > + .name = G_STRINGIFY(Name), \
> > + .desc = Desc, \
> > + .enabled = false, \
> > + }; \
> > + SPICE_CONSTRUCTOR_FUNC(G_PASTE(spice_log_category_ctor_, Name)) { \
> > + spice_log_category_register(&G_PASTE(spice_log_category_, Name));
> > \
> > + } \
> > + SPICE_DESTRUCTOR_FUNC(G_PASTE(spice_log_category_dtor_, Name)) { \
> > + spice_log_category_unregister(&G_PASTE(spice_log_category_,
> > Name));
> > \
> > + }
> > +
>
> Usually to do these stuff I use a simple "manual" list so
> I would add a "SpiceLogCategory *next" pointer to SpiceLogCategory and
> just use the constructor. This have some advantages:
> - don't need extra allocations. Other than reducing memory usage
> and fragmentation you could have some issues with system uses multiple
> allocators (well, sometimes happens on some weird systems like
> Windows);
> - there are no possible allocation failure (well, should be rare at
> startup but if you are paranoid... you are paranoid!);
> - you don't need destructor. The entire list will be freed as part of
> memory unmapping.
>
> I found weird the capital names for parameters.
Ok
>
> I also would prefer ## instead of G_PASTE, this syntax was introduced
> as standard in C preprocessors quite some time ago. In the same patch
> you are using __VA_ARGS__ with is much more recent.
>
G_PASTE is not about portability, it's mostly about readability but it also deals with some macro expansions issues, when it's nested iirc.
> > +#define SPICE_LOG_ENABLED(Name) \
> > + G_UNLIKELY(G_PASTE(spice_log_category_, Name).enabled)
> > +
>
> OT: wondering if this G_PASTE(spice_log_category_, Name).enabled could
> be make a compile time constant in some way so to optimize out.
>
> > +#if G_LOG_USE_STRUCTURED
> > +/* override future deprecation warning */
> > +#define g_log_structured(Domain, Level, ...) G_STMT_START { \
> > + G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
> > + g_log_structured(Domain, Level, ## __VA_ARGS__); \
> > + G_GNUC_END_IGNORE_DEPRECATIONS \
> > +} G_STMT_END
> > +
> > +#define spice_log(Name, Msg, ...) G_STMT_START { \
> > + if (SPICE_LOG_ENABLED(Name)) { \
> > + g_log_structured(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, \
> > + "CODE_FILE", __FILE__, \
> > + "CODE_LINE", G_STRINGIFY(__LINE__), \
> > + "CODE_FUNC", G_STRFUNC, \
> > + "SPICE_LOG_CATEGORY", G_STRINGIFY(Name), \
> > + "MESSAGE", G_STRINGIFY(Name)": " Msg, ##
> > __VA_ARGS__); \
> > + } \
> > +} G_STMT_END
> > +#else /* !G_LOG_USE_STRUCTURED */
> > +#define spice_log(Name, Msg, ...) G_STMT_START { \
> > + if (SPICE_LOG_ENABLED(Name)) { \
> > + g_debug(G_STRINGIFY(Name)": " Msg, ## __VA_ARGS__); \
> > + } \
> > +} G_STMT_END
> > +#endif
> > +
> > +void spice_log_category_register(SpiceLogCategory *cat);
> > +void spice_log_category_unregister(SpiceLogCategory *cat);
> > +void spice_log_init(void);
> > +
> > /* deprecated, please use glib directly */
> > #define spice_return_if_fail(x) g_return_if_fail(x)
> > #define spice_return_val_if_fail(x, val) g_return_val_if_fail(x, val)
> > @@ -36,7 +93,7 @@ G_BEGIN_DECLS
> > #define spice_assert(x) g_assert(x)
> > #define spice_static_assert(x) G_STATIC_ASSERT(x)
> >
> > -/* deprecated */
> > +/* deprecated, use spice_log() instead */
> > #ifndef SPICE_LOG_DOMAIN
> > #define SPICE_LOG_DOMAIN __FILE__
> > #endif
> > @@ -61,7 +118,20 @@ static inline void _spice_debug(const char *domain,
> > const
> > char *file,
> > if (msg) {
> > g_string_append_vprintf(s, msg, args);
> > }
> > +#if G_LOG_USE_STRUCTURED
> > + G_GNUC_BEGIN_IGNORE_DEPRECATIONS
> > + const GLogField fields[] = {
> > + { "GLIB_DOMAIN", G_LOG_DOMAIN, -1 },
> > + { "MESSAGE", s->str, -1 },
> > + { "CODE_FILE", file, -1 },
> > + { "CODE_LINE", line, -1 },
> > + { "CODE_FUNC", func, -1 },
> > + };
> > + g_log_structured_array(G_LOG_LEVEL_DEBUG, fields,
> > G_N_ELEMENTS(fields));
> > + G_GNUC_END_IGNORE_DEPRECATIONS
> > +#else
> > g_debug("%s", s->str);
> > +#endif
> > va_end(args);
> > g_string_free(s, true);
> > }
> > diff --git a/tests/test-logging.c b/tests/test-logging.c
> > index 03f367a..cfe63e4 100644
> > --- a/tests/test-logging.c
> > +++ b/tests/test-logging.c
> > @@ -87,6 +87,7 @@ int main(int argc, char **argv)
> > fatal_mask = (GLogLevelFlags)g_log_set_always_fatal((GLogLevelFlags)
> > G_LOG_FATAL_MASK);
> >
> > g_test_init(&argc, &argv, NULL);
> > + spice_log_init();
> >
> > /* Reset fatal mask set by g_test_init() as we don't want
> > * warnings/criticals to be fatal by default since this is what some
> > of
> > the
>
> Frediano
>
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