perf tools: Add parse_events_error interface

Adding support to return error information from parse_events function.
Following struct will be populated by parse_events function on return:

  struct parse_events_error {
    int   idx;
    char *str;
    char *help;
  };

where 'idx' is the position in the string where the parsing failed,
'str' contains dynamically allocated error string describing the error
and 'help' is optional help string.

The change contains reporting function, which currently does not display
anything. The code changes to supply error data for specific event types
are coming in next patches. However this is what the expected output is:

  $ sudo perf record -e 'sched:krava' ls
  event syntax error: 'sched:krava'
                       \___ unknown tracepoint
  ...

  $ perf record -e 'cpu/even=0x1/' ls
  event syntax error: 'cpu/even=0x1/'
                           \___ unknown term

  valid terms: pc,any,inv,edge,cmask,event,in_tx,ldlat,umask,in_tx_cp,offcore_rsp,config,config1,config2,name,period,branch_type
  ...

  $ perf record -e cycles,cache-mises ls
  event syntax error: '..es,cache-mises'
                                 \___ parser error
  ...

The output functions cut the beginning of the event string so the error
starts up to 10th character and cut the end of the string of it crosses
the terminal width.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1429729824-13932-2-git-send-email-jolsa@kernel.org
[ Renamed 'error' variables to 'err', not to clash with util.h error() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 52a2dda4f954..5ac2ffa0a145 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -12,6 +12,7 @@
 struct list_head;
 struct perf_evsel;
 struct perf_evlist;
+struct parse_events_error;
 
 struct option;
 
@@ -29,7 +30,8 @@ const char *event_type(int type);
 
 extern int parse_events_option(const struct option *opt, const char *str,
 			       int unset);
-extern int parse_events(struct perf_evlist *evlist, const char *str);
+extern int parse_events(struct perf_evlist *evlist, const char *str,
+			struct parse_events_error *error);
 extern int parse_events_terms(struct list_head *terms, const char *str);
 extern int parse_filter(const struct option *opt, const char *str, int unset);
 
@@ -74,10 +76,17 @@ struct parse_events_term {
 	bool used;
 };
 
+struct parse_events_error {
+	int   idx;	/* index in the parsed string */
+	char *str;      /* string to display at the index */
+	char *help;	/* optional help string */
+};
+
 struct parse_events_evlist {
-	struct list_head list;
-	int idx;
-	int nr_groups;
+	struct list_head	   list;
+	int			   idx;
+	int			   nr_groups;
+	struct parse_events_error *error;
 };
 
 struct parse_events_terms {
@@ -114,6 +123,8 @@ void parse_events__set_leader(char *name, struct list_head *list);
 void parse_events_update_lists(struct list_head *list_event,
 			       struct list_head *list_all);
 void parse_events_error(void *data, void *scanner, char const *msg);
+void parse_events_evlist_error(struct parse_events_evlist *data,
+			       int idx, const char *str);
 
 void print_events(const char *event_glob, bool name_only);