Implement simpleperf list subcommand.

simpleperf is used to replace linux/tools/perf. And This CL implements
the list subcommand of it.

Change-Id: I3e6fe854e19cc370070d0fd8416d0aa6fa8f8e90
diff --git a/simpleperf/event_attr.h b/simpleperf/event_attr.h
new file mode 100644
index 0000000..30052f1
--- /dev/null
+++ b/simpleperf/event_attr.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SIMPLE_PERF_EVENT_ATTR_H_
+#define SIMPLE_PERF_EVENT_ATTR_H_
+
+#include <stdint.h>
+#include <string>
+
+#include "perf_event.h"
+
+struct EventType;
+
+// EventAttr manages perf_event_attr, which provides detailed configuration information when
+// opening a perf_event_file. The configuration information tells the kernel how to count and
+// record events.
+class EventAttr {
+ public:
+  static EventAttr CreateDefaultAttrToMonitorEvent(const EventType& event_type);
+
+  EventAttr(const perf_event_attr& attr) : attr_(attr) {
+  }
+
+  perf_event_attr Attr() const {
+    return attr_;
+  }
+
+  uint64_t SampleType() const {
+    return attr_.sample_type;
+  }
+
+  void EnableOnExec() {
+    attr_.enable_on_exec = 1;
+  }
+
+  void SetSampleFreq(uint64_t freq) {
+    attr_.freq = 1;
+    attr_.sample_freq = freq;
+  }
+
+  void SetSamplePeriod(uint64_t period) {
+    attr_.freq = 0;
+    attr_.sample_period = period;
+  }
+
+  void SetSampleAll() {
+    attr_.sample_id_all = 1;
+  }
+
+  void Dump(size_t indent = 0) const;
+
+ private:
+  perf_event_attr attr_;
+};
+
+#endif  // SIMPLE_PERF_EVENT_ATTR_H_