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
diff --git a/libbacktrace/UnwindCurrent.h b/libbacktrace/UnwindCurrent.h
new file mode 100644
index 0000000..7dc977d
--- /dev/null
+++ b/libbacktrace/UnwindCurrent.h
@@ -0,0 +1,56 @@
+/*
+ * 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_UNWIND_CURRENT_H
+#define _LIBBACKTRACE_UNWIND_CURRENT_H
+
+#include <string>
+
+#include "Backtrace.h"
+#include "BacktraceThread.h"
+
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+
+class UnwindCurrent : public BacktraceImpl {
+public:
+  UnwindCurrent();
+  virtual ~UnwindCurrent();
+
+  virtual bool Unwind(size_t num_ignore_frames);
+
+  virtual std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset);
+
+  bool UnwindFromContext(size_t num_ignore_frames, bool resolve);
+
+  void ExtractContext(void* sigcontext);
+
+protected:
+  unw_context_t context_;
+};
+
+class UnwindThread : public UnwindCurrent, public BacktraceThreadInterface {
+public:
+  UnwindThread();
+  virtual ~UnwindThread();
+
+  virtual bool Init();
+
+  virtual void ThreadUnwind(
+      siginfo_t* siginfo, void* sigcontext, size_t num_ignore_frames);
+};
+
+#endif // _LIBBACKTRACE_UNWIND_CURRENT_H