Installd: Introduce otapreopt

Add a tool for dexopt during OTA. The tool will use /data/ota as
an ANDROID_ROOT wrt/ the dalvik-cache, compiling a new boot image
and system apps into this directory. Other apps will be compiled
to odex files suffixed with ".b".

Bug: 25612095
Change-Id: I6ac382973f13850f6b37402a1b2330c0014b47d9
diff --git a/cmds/installd/system_properties.h b/cmds/installd/system_properties.h
new file mode 100644
index 0000000..1b5fb3a
--- /dev/null
+++ b/cmds/installd/system_properties.h
@@ -0,0 +1,89 @@
+/*
+ * 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 OTAPREOPT_SYSTEM_PROPERTIES_H_
+#define OTAPREOPT_SYSTEM_PROPERTIES_H_
+
+#include <fstream>
+#include <string>
+#include <unordered_map>
+
+namespace android {
+namespace installd {
+
+// Helper class to read system properties into and manage as a string->string map.
+class SystemProperties {
+ public:
+    bool Load(const std::string& strFile) {
+        std::ifstream input_stream(strFile);
+
+        if (!input_stream.is_open()) {
+            return false;
+        }
+
+        while (!input_stream.eof()) {
+            // Read the next line.
+            std::string line;
+            getline(input_stream, line);
+
+            // Is the line empty? Simplifies the next check.
+            if (line.empty()) {
+                continue;
+            }
+
+            // Is this a comment (starts with pound)?
+            if (line[0] == '#') {
+                continue;
+            }
+
+            size_t equals_pos = line.find('=');
+            if (equals_pos == std::string::npos || equals_pos == 0) {
+                // Did not find equals sign, or it's the first character - isn't a valid line.
+                continue;
+            }
+
+            std::string key = line.substr(0, equals_pos);
+            std::string value = line.substr(equals_pos + 1,
+                                            line.length() - equals_pos + 1);
+
+            properties_.insert(std::make_pair(key, value));
+        }
+
+        return true;
+    }
+
+    // Look up the key in the map. Returns null if the key isn't mapped.
+    const std::string* GetProperty(const std::string& key) const {
+        auto it = properties_.find(key);
+        if (it != properties_.end()) {
+            return &it->second;
+        }
+        return nullptr;
+    }
+
+    void SetProperty(const std::string& key, const std::string& value) {
+        properties_.insert(std::make_pair(key, value));
+    }
+
+ private:
+    // The actual map.
+    std::unordered_map<std::string, std::string> properties_;
+};
+
+}  // namespace installd
+}  // namespace android
+
+#endif  // OTAPREOPT_SYSTEM_PROPERTIES_H_