Expose PngHandler via resources.h.
As a private header for testing purpose. PngHandler additionally loads a
given filename if the one with '/res/images' prefix is not available. It
also provides color_type/bit_depth that are parsed from the PNG file.
This allows reusing the same code for the ResourcesTest (renamed from
ResourceTest).
Test: Run recovery_manual_test on marlin.
Change-Id: I3f939d79a1cb1b83a899847dbe2d51bde15d16d8
diff --git a/minui/include/private/resources.h b/minui/include/private/resources.h
new file mode 100644
index 0000000..2a83a10
--- /dev/null
+++ b/minui/include/private/resources.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#pragma once
+
+#include <stdio.h>
+
+#include <memory>
+#include <string>
+
+#include <png.h>
+
+// This class handles the PNG file parsing. It also holds the ownership of the PNG pointer and the
+// opened file pointer. Both will be destroyed / closed when this object goes out of scope.
+class PngHandler {
+ public:
+ // Constructs an instance by loading the PNG file from '/res/images/<name>.png', or '<name>'.
+ PngHandler(const std::string& name);
+
+ ~PngHandler();
+
+ png_uint_32 width() const {
+ return width_;
+ }
+
+ png_uint_32 height() const {
+ return height_;
+ }
+
+ png_byte channels() const {
+ return channels_;
+ }
+
+ int bit_depth() const {
+ return bit_depth_;
+ }
+
+ int color_type() const {
+ return color_type_;
+ }
+
+ png_structp png_ptr() const {
+ return png_ptr_;
+ }
+
+ png_infop info_ptr() const {
+ return info_ptr_;
+ }
+
+ int error_code() const {
+ return error_code_;
+ };
+
+ operator bool() const {
+ return error_code_ == 0;
+ }
+
+ private:
+ png_structp png_ptr_{ nullptr };
+ png_infop info_ptr_{ nullptr };
+ png_uint_32 width_;
+ png_uint_32 height_;
+ png_byte channels_;
+ int bit_depth_;
+ int color_type_;
+
+ // The |error_code_| is set to a negative value if an error occurs when opening the png file.
+ int error_code_{ 0 };
+ // After initialization, we'll keep the file pointer open before destruction of PngHandler.
+ std::unique_ptr<FILE, decltype(&fclose)> png_fp_{ nullptr, fclose };
+};