Merge master

2 files changed, 125 insertions, 78 deletions

diff --git a/src/core/lib/debug/trace.cc b/src/core/lib/debug/trace.cc
index 9c75ef124a..4c63983bdc 100644
--- a/src/core/lib/debug/trace.cc
+++ b/src/core/lib/debug/trace.cc
@@ -27,26 +27,61 @@
 
 int grpc_tracer_set_enabled(const char* name, int enabled);
 
-typedef struct tracer {
-  grpc_tracer_flag* flag;
-  struct tracer* next;
-} tracer;
-static tracer* tracers;
-
-#ifdef GRPC_THREADSAFE_TRACER
-#define TRACER_SET(flag, on) gpr_atm_no_barrier_store(&(flag).value, (on))
-#else
-#define TRACER_SET(flag, on) (flag).value = (on)
-#endif
-
-void grpc_register_tracer(grpc_tracer_flag* flag) {
-  tracer* t = (tracer*)gpr_malloc(sizeof(*t));
-  t->flag = flag;
-  t->next = tracers;
-  TRACER_SET(*flag, false);
-  tracers = t;
+namespace grpc_core {
+
+TraceFlag* TraceFlagList::root_tracer_ = nullptr;
+
+bool TraceFlagList::Set(const char* name, bool enabled) {
+  TraceFlag* t;
+  if (0 == strcmp(name, "all")) {
+    for (t = root_tracer_; t; t = t->next_tracer_) {
+      t->set_enabled(enabled);
+    }
+  } else if (0 == strcmp(name, "list_tracers")) {
+    LogAllTracers();
+  } else if (0 == strcmp(name, "refcount")) {
+    for (t = root_tracer_; t; t = t->next_tracer_) {
+      if (strstr(t->name_, "refcount") != nullptr) {
+        t->set_enabled(enabled);
+      }
+    }
+  } else {
+    bool found = false;
+    for (t = root_tracer_; t; t = t->next_tracer_) {
+      if (0 == strcmp(name, t->name_)) {
+        t->set_enabled(enabled);
+        found = true;
+      }
+    }
+    if (!found) {
+      gpr_log(GPR_ERROR, "Unknown trace var: '%s'", name);
+      return false; /* early return */
+    }
+  }
+  return true;
+}
+
+void TraceFlagList::Add(TraceFlag* flag) {
+  flag->next_tracer_ = root_tracer_;
+  root_tracer_ = flag;
 }
 
+void TraceFlagList::LogAllTracers() {
+  gpr_log(GPR_DEBUG, "available tracers:");
+  TraceFlag* t;
+  for (t = root_tracer_; t != nullptr; t = t->next_tracer_) {
+    gpr_log(GPR_DEBUG, "\t%s", t->name_);
+  }
+}
+
+// Flags register themselves on the list during construction
+TraceFlag::TraceFlag(bool default_enabled, const char* name)
+    : name_(name), value_(default_enabled) {
+  TraceFlagList::Add(this);
+}
+
+}  // namespace grpc_core
+
 static void add(const char* beg, const char* end, char*** ss, size_t* ns) {
   size_t n = *ns;
   size_t np = n + 1;
@@ -80,9 +115,9 @@ static void parse(const char* s) {
 
   for (i = 0; i < nstrings; i++) {
     if (strings[i][0] == '-') {
-      grpc_tracer_set_enabled(strings[i] + 1, 0);
+      grpc_core::TraceFlagList::Set(strings[i] + 1, false);
     } else {
-      grpc_tracer_set_enabled(strings[i], 1);
+      grpc_core::TraceFlagList::Set(strings[i], true);
     }
   }
 
@@ -92,14 +127,6 @@ static void parse(const char* s) {
   gpr_free(strings);
 }
 
-static void list_tracers() {
-  gpr_log(GPR_DEBUG, "available tracers:");
-  tracer* t;
-  for (t = tracers; t; t = t->next) {
-    gpr_log(GPR_DEBUG, "\t%s", t->flag->name);
-  }
-}
-
 void grpc_tracer_init(const char* env_var) {
   char* e = gpr_getenv(env_var);
   if (e != nullptr) {
@@ -108,40 +135,8 @@ void grpc_tracer_init(const char* env_var) {
   }
 }
 
-void grpc_tracer_shutdown(void) {
-  while (tracers) {
-    tracer* t = tracers;
-    tracers = t->next;
-    gpr_free(t);
-  }
-}
+void grpc_tracer_shutdown(void) {}
 
 int grpc_tracer_set_enabled(const char* name, int enabled) {
-  tracer* t;
-  if (0 == strcmp(name, "all")) {
-    for (t = tracers; t; t = t->next) {
-      TRACER_SET(*t->flag, enabled);
-    }
-  } else if (0 == strcmp(name, "list_tracers")) {
-    list_tracers();
-  } else if (0 == strcmp(name, "refcount")) {
-    for (t = tracers; t; t = t->next) {
-      if (strstr(t->flag->name, "refcount") != nullptr) {
-        TRACER_SET(*t->flag, enabled);
-      }
-    }
-  } else {
-    int found = 0;
-    for (t = tracers; t; t = t->next) {
-      if (0 == strcmp(name, t->flag->name)) {
-        TRACER_SET(*t->flag, enabled);
-        found = 1;
-      }
-    }
-    if (!found) {
-      gpr_log(GPR_ERROR, "Unknown trace var: '%s'", name);
-      return 0; /* early return */
-    }
-  }
-  return 1;
+  return grpc_core::TraceFlagList::Set(name, enabled != 0);
 }
diff --git a/src/core/lib/debug/trace.h b/src/core/lib/debug/trace.h
index 7447d5d94a..b58c16f3ca 100644
--- a/src/core/lib/debug/trace.h
+++ b/src/core/lib/debug/trace.h
@@ -27,37 +27,89 @@
 extern "C" {
 #endif
 
+void grpc_tracer_init(const char* env_var_name);
+void grpc_tracer_shutdown(void);
+
+#ifdef __cplusplus
+}
+#endif
+
 #if defined(__has_feature)
 #if __has_feature(thread_sanitizer)
 #define GRPC_THREADSAFE_TRACER
 #endif
 #endif
 
-typedef struct {
+#ifdef __cplusplus
+
+namespace grpc_core {
+
+class TraceFlag;
+class TraceFlagList {
+ public:
+  static bool Set(const char* name, bool enabled);
+  static void Add(TraceFlag* flag);
+
+ private:
+  static void LogAllTracers();
+  static TraceFlag* root_tracer_;
+};
+
+namespace testing {
+void grpc_tracer_enable_flag(grpc_core::TraceFlag* flag);
+}
+
+class TraceFlag {
+ public:
+  TraceFlag(bool default_enabled, const char* name);
+  ~TraceFlag() {}
+
+  const char* name() const { return name_; }
+
+  bool enabled() {
+#ifdef GRPC_THREADSAFE_TRACER
+    return gpr_atm_no_barrier_load(&value_) != 0;
+#else
+    return value_;
+#endif
+  }
+
+ private:
+  friend void grpc_core::testing::grpc_tracer_enable_flag(TraceFlag* flag);
+  friend class TraceFlagList;
+
+  void set_enabled(bool enabled) {
 #ifdef GRPC_THREADSAFE_TRACER
-  gpr_atm value;
+    gpr_atm_no_barrier_store(&value_, enabled);
 #else
-  bool value;
+    value_ = enabled;
 #endif
-  const char* name;
-} grpc_tracer_flag;
+  }
 
+  TraceFlag* next_tracer_;
+  const char* const name_;
 #ifdef GRPC_THREADSAFE_TRACER
-#define GRPC_TRACER_ON(flag) (gpr_atm_no_barrier_load(&(flag).value) != 0)
-#define GRPC_TRACER_INITIALIZER(on, name) \
-  { (gpr_atm)(on), (name) }
+  gpr_atm value_;
 #else
-#define GRPC_TRACER_ON(flag) ((flag).value)
-#define GRPC_TRACER_INITIALIZER(on, name) \
-  { (on), (name) }
+  bool value_;
 #endif
+};
 
-void grpc_register_tracer(grpc_tracer_flag* flag);
-void grpc_tracer_init(const char* env_var_name);
-void grpc_tracer_shutdown(void);
+#ifndef NDEBUG
+typedef TraceFlag DebugOnlyTraceFlag;
+#else
+class DebugOnlyTraceFlag {
+ public:
+  DebugOnlyTraceFlag(bool default_enabled, const char* name) {}
+  bool enabled() { return false; }
 
-#ifdef __cplusplus
-}
+ private:
+  void set_enabled(bool enabled) {}
+};
 #endif
 
+}  // namespace grpc_core
+
+#endif  // __cplusplus
+
 #endif /* GRPC_CORE_LIB_DEBUG_TRACE_H */