Rewrite libbacktrace using C++.

The old code was essentially trying to be C++ in C and was awkward. This
change makes it all objects with a thin layer that C code can use.

There is a C++ backtrace object that is not very useful, this code will
replace it.

This change also includes moving the backtrace test to a gtest, and adding
coverage of all major functionality.

Bug: 8410085
Change-Id: Iae0f1b09b3dd60395f71ed66010c1ea5cdd37841

1 files changed, 93 insertions, 0 deletions

diff --git a/libbacktrace/BacktraceThread.h b/libbacktrace/BacktraceThread.h
new file mode 100644
index 0000000..afea771
--- /dev/null
+++ b/libbacktrace/BacktraceThread.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2013 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 _LIBBACKTRACE_BACKTRACE_THREAD_H
+#define _LIBBACKTRACE_BACKTRACE_THREAD_H
+
+#include <inttypes.h>
+#include <pthread.h>
+#include <sys/types.h>
+
+#include "Backtrace.h"
+
+typedef enum {
+  STATE_WAITING = 0,
+  STATE_DUMPING,
+  STATE_DONE,
+  STATE_CANCEL,
+} state_e;
+
+class BacktraceThreadInterface;
+
+class ThreadEntry {
+public:
+  ThreadEntry(
+      BacktraceThreadInterface* impl, pid_t pid, pid_t tid,
+      size_t num_ignore_frames);
+  ~ThreadEntry();
+
+  bool Match(pid_t pid, pid_t tid) { return (pid == pid_ && tid == tid_); }
+
+  static ThreadEntry* AddThreadToUnwind(
+      BacktraceThreadInterface* thread_intf, pid_t pid, pid_t tid,
+      size_t num_ignored_frames);
+
+  BacktraceThreadInterface* thread_intf_;
+  pid_t pid_;
+  pid_t tid_;
+  ThreadEntry* next_;
+  ThreadEntry* prev_;
+  int32_t state_;
+  int num_ignore_frames_;
+};
+
+// Interface class that does not contain any local storage, only defines
+// virtual functions to be defined by subclasses.
+class BacktraceThreadInterface {
+public:
+  virtual ~BacktraceThreadInterface() { }
+
+  virtual bool Init() = 0;
+
+  virtual void ThreadUnwind(
+      siginfo_t* siginfo, void* sigcontext, size_t num_ignore_frames) = 0;
+};
+
+class BacktraceThread : public BacktraceCurrent {
+public:
+  // impl and thread_intf should point to the same object, this allows
+  // the compiler to catch if an implementation does not properly
+  // subclass both.
+  BacktraceThread(
+      BacktraceImpl* impl, BacktraceThreadInterface* thread_intf, pid_t tid);
+  virtual ~BacktraceThread();
+
+  virtual bool Unwind(size_t num_ignore_frames);
+
+  virtual void ThreadUnwind(
+      siginfo_t* siginfo, void* sigcontext, size_t num_ignore_frames) {
+    thread_intf_->ThreadUnwind(siginfo, sigcontext, num_ignore_frames);
+  }
+
+private:
+  virtual bool TriggerUnwindOnThread(ThreadEntry* entry);
+
+  virtual void FinishUnwind();
+
+  BacktraceThreadInterface* thread_intf_;
+};
+
+#endif // _LIBBACKTRACE_BACKTRACE_THREAD_H