Implement maps parsing.

The MapsOffline code is still in development so I'm not testing it very
thoroughly yet.

Bug: 23762183

Test: All unit tests pass.
Change-Id: I77aeac62940cd95c489ee221afe02349bfe39671
diff --git a/libunwindstack/Maps.h b/libunwindstack/Maps.h
new file mode 100644
index 0000000..239b64a
--- /dev/null
+++ b/libunwindstack/Maps.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2016 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 _LIBUNWINDSTACK_MAPS_H
+#define _LIBUNWINDSTACK_MAPS_H
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "Elf.h"
+#include "MapInfo.h"
+
+// Special flag to indicate a map is in /dev/. However, a map in
+// /dev/ashmem/... does not set this flag.
+static constexpr int MAPS_FLAGS_DEVICE_MAP = 0x8000;
+
+class Maps {
+ public:
+  Maps() = default;
+  virtual ~Maps();
+
+  MapInfo* Find(uint64_t pc);
+
+  bool ParseLine(const char* line, MapInfo* map_info);
+
+  virtual bool Parse();
+
+  virtual const std::string GetMapsFile() const { return ""; }
+
+  typedef std::vector<MapInfo>::iterator iterator;
+  iterator begin() { return maps_.begin(); }
+  iterator end() { return maps_.end(); }
+
+  typedef std::vector<MapInfo>::const_iterator const_iterator;
+  const_iterator begin() const { return maps_.begin(); }
+  const_iterator end() const { return maps_.end(); }
+
+  size_t Total() { return maps_.size(); }
+
+ protected:
+  std::vector<MapInfo> maps_;
+};
+
+class RemoteMaps : public Maps {
+ public:
+  RemoteMaps(pid_t pid) : pid_(pid) {}
+  virtual ~RemoteMaps() = default;
+
+  virtual const std::string GetMapsFile() const override;
+
+ private:
+  pid_t pid_;
+};
+
+class LocalMaps : public RemoteMaps {
+ public:
+  LocalMaps() : RemoteMaps(getpid()) {}
+  virtual ~LocalMaps() = default;
+};
+
+class BufferMaps : public Maps {
+ public:
+  BufferMaps(const char* buffer) : buffer_(buffer) {}
+  virtual ~BufferMaps() = default;
+
+  bool Parse() override;
+
+ private:
+  const char* buffer_;
+};
+
+class FileMaps : public Maps {
+ public:
+  FileMaps(const std::string& file) : file_(file) {}
+  virtual ~FileMaps() = default;
+
+  const std::string GetMapsFile() const override { return file_; }
+
+ protected:
+  const std::string file_;
+};
+
+class OfflineMaps : public FileMaps {
+ public:
+  OfflineMaps(const std::string& file) : FileMaps(file) {}
+  virtual ~OfflineMaps() = default;
+
+  bool Parse() override;
+};
+
+#endif  // _LIBUNWINDSTACK_MAPS_H