[Qemu-devel] [PATCH v2 2/6] trace: convert code to use event iterators

["Daniel P. Berrange" <berrange@redhat.com>]

This converts the HMP/QMP monitor API implementations
and some internal trace control methods to use the new
trace event iterator APIs.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 monitor.c       | 16 ++++++----
 trace/control.c | 94 ++++++++++++++++++++++++++++++++++-----------------------
 trace/qmp.c     | 16 ++++++----
 3 files changed, 76 insertions(+), 50 deletions(-)

diff --git a/monitor.c b/monitor.c
index 5c00373..7b979a6 100644
--- a/monitor.c
+++ b/monitor.c
@@ -3335,9 +3335,11 @@ void info_trace_events_completion(ReadLineState *rs, int nb_args, const char *st
     len = strlen(str);
     readline_set_completion_index(rs, len);
     if (nb_args == 2) {
-        TraceEventID id;
-        for (id = 0; id < trace_event_count(); id++) {
-            const char *event_name = trace_event_get_name(trace_event_id(id));
+        TraceEventIter iter;
+        TraceEvent *ev;
+        trace_event_iter_init(&iter, NULL);
+        while ((ev = trace_event_iter_next(&iter)) != NULL) {
+            const char *event_name = trace_event_get_name(ev);
             if (!strncmp(str, event_name, len)) {
                 readline_add_completion(rs, event_name);
             }
@@ -3352,9 +3354,11 @@ void trace_event_completion(ReadLineState *rs, int nb_args, const char *str)
     len = strlen(str);
     readline_set_completion_index(rs, len);
     if (nb_args == 2) {
-        TraceEventID id;
-        for (id = 0; id < trace_event_count(); id++) {
-            const char *event_name = trace_event_get_name(trace_event_id(id));
+        TraceEventIter iter;
+        TraceEvent *ev;
+        trace_event_iter_init(&iter, NULL);
+        while ((ev = trace_event_iter_next(&iter)) != NULL) {
+            const char *event_name = trace_event_get_name(ev);
             if (!strncmp(str, event_name, len)) {
                 readline_add_completion(rs, event_name);
             }
diff --git a/trace/control.c b/trace/control.c
index b871727..8fa7ed6 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -60,9 +60,10 @@ TraceEvent *trace_event_name(const char *name)
 {
     assert(name != NULL);
 
-    TraceEventID i;
-    for (i = 0; i < trace_event_count(); i++) {
-        TraceEvent *ev = trace_event_id(i);
+    TraceEventIter iter;
+    TraceEvent *ev;
+    trace_event_iter_init(&iter, NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (strcmp(trace_event_get_name(ev), name) == 0) {
             return ev;
         }
@@ -105,21 +106,20 @@ TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
 {
     assert(pat != NULL);
 
-    TraceEventID i;
-
-    if (ev == NULL) {
-        i = -1;
-    } else {
-        i = trace_event_get_id(ev);
-    }
-    i++;
-
-    while (i < trace_event_count()) {
-        TraceEvent *res = trace_event_id(i);
-        if (pattern_glob(pat, trace_event_get_name(res))) {
-            return res;
+    bool matched = ev ? false : true;
+    TraceEventIter iter;
+    TraceEvent *thisev;
+    trace_event_iter_init(&iter, NULL);
+    while ((thisev = trace_event_iter_next(&iter)) != NULL) {
+        if (matched) {
+            if (pattern_glob(pat, trace_event_get_name(thisev))) {
+                return thisev;
+            }
+        } else {
+            if (ev == thisev) {
+                matched = true;
+            }
         }
-        i++;
     }
 
     return NULL;
@@ -147,10 +147,11 @@ TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 
 void trace_list_events(void)
 {
-    int i;
-    for (i = 0; i < trace_event_count(); i++) {
-        TraceEvent *res = trace_event_id(i);
-        fprintf(stderr, "%s\n", trace_event_get_name(res));
+    TraceEventIter iter;
+    TraceEvent *ev;
+    trace_event_iter_init(&iter, NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        fprintf(stderr, "%s\n", trace_event_get_name(ev));
     }
 }
 
@@ -158,25 +159,40 @@ static void do_trace_enable_events(const char *line_buf)
 {
     const bool enable = ('-' != line_buf[0]);
     const char *line_ptr = enable ? line_buf : line_buf + 1;
-
-    if (trace_event_is_pattern(line_ptr)) {
-        TraceEvent *ev = NULL;
-        while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
+    TraceEventIter iter;
+    TraceEvent *ev;
+    bool is_pattern = trace_event_is_pattern(line_ptr);
+
+    trace_event_iter_init(&iter, is_pattern ? line_ptr : NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        bool match = false;
+        if (is_pattern) {
             if (trace_event_get_state_static(ev)) {
-                trace_event_set_state_dynamic_init(ev, enable);
+                match = true;
             }
-        }
-    } else {
-        TraceEvent *ev = trace_event_name(line_ptr);
-        if (ev == NULL) {
-            error_report("WARNING: trace event '%s' does not exist",
-                         line_ptr);
-        } else if (!trace_event_get_state_static(ev)) {
-            error_report("WARNING: trace event '%s' is not traceable",
-                         line_ptr);
         } else {
-            trace_event_set_state_dynamic_init(ev, enable);
+            if (g_str_equal(trace_event_get_name(ev),
+                            line_ptr)) {
+                if (!trace_event_get_state_static(ev)) {
+                    error_report("WARNING: trace event '%s' is not traceable",
+                                 line_ptr);
+                    return;
+                }
+                match = true;
+            }
         }
+        if (match) {
+            /* start tracing */
+            trace_event_set_state_dynamic(ev, enable);
+            if (!is_pattern) {
+                return;
+            }
+        }
+    }
+
+    if (!is_pattern) {
+        error_report("WARNING: trace event '%s' does not exist",
+                     line_ptr);
     }
 }
 
@@ -292,8 +308,10 @@ char *trace_opt_parse(const char *optarg)
 
 void trace_init_vcpu_events(void)
 {
-    TraceEvent *ev = NULL;
-    while ((ev = trace_event_pattern("*", ev)) != NULL) {
+    TraceEventIter iter;
+    TraceEvent *ev;
+    trace_event_iter_init(&iter, NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (trace_event_is_vcpu(ev) &&
             trace_event_get_state_static(ev) &&
             trace_event_get_state_dynamic(ev)) {
diff --git a/trace/qmp.c b/trace/qmp.c
index 11d2564..88a907b 100644
--- a/trace/qmp.c
+++ b/trace/qmp.c
@@ -52,8 +52,10 @@ static bool check_events(bool has_vcpu, bool ignore_unavailable, bool is_pattern
         return true;
     } else {
         /* error for unavailable events */
-        TraceEvent *ev = NULL;
-        while ((ev = trace_event_pattern(name, ev)) != NULL) {
+        TraceEventIter iter;
+        TraceEvent *ev;
+        trace_event_iter_init(&iter, name);
+        while ((ev = trace_event_iter_next(&iter)) != NULL) {
             if (!ignore_unavailable && !trace_event_get_state_static(ev)) {
                 error_setg(errp, "event \"%s\" is disabled", trace_event_get_name(ev));
                 return false;
@@ -69,6 +71,7 @@ TraceEventInfoList *qmp_trace_event_get_state(const char *name,
 {
     Error *err = NULL;
     TraceEventInfoList *events = NULL;
+    TraceEventIter iter;
     TraceEvent *ev;
     bool is_pattern = trace_event_is_pattern(name);
     CPUState *cpu;
@@ -86,8 +89,8 @@ TraceEventInfoList *qmp_trace_event_get_state(const char *name,
     }
 
     /* Get states (all errors checked above) */
-    ev = NULL;
-    while ((ev = trace_event_pattern(name, ev)) != NULL) {
+    trace_event_iter_init(&iter, is_pattern ? name : NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
         TraceEventInfoList *elem;
         bool is_vcpu = trace_event_is_vcpu(ev);
         if (has_vcpu && !is_vcpu) {
@@ -132,6 +135,7 @@ void qmp_trace_event_set_state(const char *name, bool enable,
                                Error **errp)
 {
     Error *err = NULL;
+    TraceEventIter iter;
     TraceEvent *ev;
     bool is_pattern = trace_event_is_pattern(name);
     CPUState *cpu;
@@ -150,8 +154,8 @@ void qmp_trace_event_set_state(const char *name, bool enable,
     }
 
     /* Apply changes (all errors checked above) */
-    ev = NULL;
-    while ((ev = trace_event_pattern(name, ev)) != NULL) {
+    trace_event_iter_init(&iter, name);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (!trace_event_get_state_static(ev) ||
             (has_vcpu && !trace_event_is_vcpu(ev))) {
             continue;
-- 
2.7.4