checkvintf: checks compatibility between files

checkvintf is a host binary that checks compatibility
between a manifest and a matrix.

Example usage:
$ checkvintf system/libhidl/manifest.xml \
  device/foo/bar/compatibility_matrix.xml

If compatible, write "true\n" to stdout and exit status = 0.
If incompatible, write "false\n" to stdout, write
   error message to stderr, and exit status = 1.
If I/O error or parse error, write error message to
   stderr and exit status = -1.

Test: checkvintf
Change-Id: I8d4f357f80817fcc2e6216f0a9a1f5658c02cd2d
Fixes: 66966881
diff --git a/check_vintf.cpp b/check_vintf.cpp
new file mode 100644
index 0000000..211702e
--- /dev/null
+++ b/check_vintf.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include <iostream>
+
+#include <vintf/parse_xml.h>
+#include "utils.h"
+
+namespace android {
+namespace vintf {
+
+template <typename T>
+std::unique_ptr<T> readObject(const std::string& path, const XmlConverter<T>& converter) {
+    std::string xml;
+    status_t err = details::gFetcher->fetch(path, xml);
+    if (err != OK) {
+        std::cerr << "Error: Cannot read '" << path << "': " << strerror(-err) << std::endl;
+        return nullptr;
+    }
+    auto ret = std::make_unique<T>();
+    if (!converter(ret.get(), xml)) {
+        std::cerr << "Error: Cannot parse '" << path << "': " << converter.lastError() << std::endl;
+        return nullptr;
+    }
+    return ret;
+}
+
+}  // namespace vintf
+}  // namespace android
+
+int main(int argc, char** argv) {
+    using namespace android::vintf;
+    if (argc < 3) {
+        std::cerr << "usage: " << argv[0] << " <manifest.xml> <matrix.xml>" << std::endl
+                  << "    Checks compatibility between a manifest and a compatibility matrix."
+                  << std::endl;
+        return -1;
+    }
+
+    auto manifest = readObject(argv[1], gHalManifestConverter);
+    auto matrix = readObject(argv[2], gCompatibilityMatrixConverter);
+    if (manifest == nullptr || matrix == nullptr) {
+        return -1;
+    }
+
+    std::string error;
+    if (!manifest->checkCompatibility(*matrix, &error)) {
+        std::cerr << "Error: Incompatible: " << error << std::endl;
+        std::cout << "false" << std::endl;
+        return 1;
+    }
+
+    std::cout << "true" << std::endl;
+    return 0;
+}