Move File-opening of PNG image into Png constructor (#2161)

Also rename `File::c_str` to `display_name` for clarity

include/file.hpp

@@ -47,7 +47,7 @@ public:
 	}
 	std::streambuf *operator->() { return &**this; }
 
-	char const *c_str(std::string const &path) const {
+	char const *display_name(std::string const &path) const {
 		return std::holds_alternative<std::filebuf>(_file)             ? path.c_str()
 		       : std::get<std::streambuf *>(_file) == std::cin.rdbuf() ? "<stdin>"
 		                                                               : "<stdout>";

include/gfx/png.hpp

@@ -5,6 +5,7 @@
 
 #include <stdint.h>
 #include <streambuf>
+#include <string>
 #include <vector>
 
 #include "gfx/rgba.hpp"
@@ -17,7 +18,11 @@ struct Png {
 	bool isIndexed = false;
 
 	Png() {}
+	Png(std::string const &path);
 	Png(char const *filename, std::streambuf &file);
+
+private:
+	void initialize(char const *filename, std::streambuf &file);
 };
 
 #endif // RGBDS_GFX_PNG_HPP

src/gfx/main.cpp

@@ -5,7 +5,6 @@
 #include "gfx/main.hpp"
 
 #include <inttypes.h>
-#include <ios>
 #include <optional>
 #include <png.h>
 #include <stdarg.h>
@@ -19,7 +18,6 @@
 
 #include "cli.hpp"
 #include "diagnostics.hpp"
-#include "file.hpp"
 #include "helpers.hpp"
 #include "style.hpp" // style_Parse
 #include "usage.hpp"
@@ -681,14 +679,7 @@ int main(int argc, char *argv[]) {
 	bool useInputImage = !options.input.empty() && !localOptions.reverse;
 	Png png;
 	if (useInputImage) {
-		if (File image;
-		    image.open(options.input, std::ios_base::in | std::ios_base::binary) == nullptr) {
-			fatal(
-			    "Failed to open PNG image (\"%s\"): %s", image.c_str(options.input), strerror(errno)
-			);
-		} else {
-			png = Png(image.c_str(options.input), *image);
-		}
+		png = Png(options.input);
 	}
 
 	// Execute deferred pal spec parsing, now that all other params are known.

src/gfx/png.cpp

@@ -15,6 +15,7 @@
 #include <vector>
 
 #include "diagnostics.hpp"
+#include "file.hpp"
 #include "helpers.hpp"
 #include "verbosity.hpp"
 
@@ -61,7 +62,19 @@ static void readData(png_structp png, png_bytep data, size_t length) {
 	}
 }
 
+Png::Png(std::string const &path) {
+	if (File image; image.open(path, std::ios_base::in | std::ios_base::binary) == nullptr) {
+		fatal("Failed to open PNG image (\"%s\"): %s", image.display_name(path), strerror(errno));
+	} else {
+		initialize(image.display_name(path), *image);
+	}
+}
+
 Png::Png(char const *filename, std::streambuf &file) {
+	initialize(filename, file);
+}
+
+void Png::initialize(char const *filename, std::streambuf &file) {
 	Input input(filename, file);
 
 	verbosePrint(VERB_NOTICE, "Reading PNG file \"%s\"\n", input.filename);

src/gfx/process.cpp

@@ -491,7 +491,11 @@ static void outputPalettes(std::vector<Palette> const &palettes) {
 		File output;
 		if (!output.open(options.palettes, std::ios_base::out | std::ios_base::binary)) {
 			// LCOV_EXCL_START
-			fatal("Failed to create \"%s\": %s", output.c_str(options.palettes), strerror(errno));
+			fatal(
+			    "Failed to create \"%s\": %s",
+			    output.display_name(options.palettes),
+			    strerror(errno)
+			);
 			// LCOV_EXCL_STOP
 		}
 
@@ -646,7 +650,7 @@ static void outputUnoptimizedTileData(
 	File output;
 	if (!output.open(options.output, std::ios_base::out | std::ios_base::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", output.c_str(options.output), strerror(errno));
+		fatal("Failed to create \"%s\": %s", output.display_name(options.output), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 
@@ -699,7 +703,7 @@ static void outputUnoptimizedMaps(
 			file.emplace();
 			if (!file->open(path, std::ios_base::out | std::ios_base::binary)) {
 				// LCOV_EXCL_START
-				fatal("Failed to create \"%s\": %s", file->c_str(path), strerror(errno));
+				fatal("Failed to create \"%s\": %s", file->display_name(path), strerror(errno));
 				// LCOV_EXCL_STOP
 			}
 		}
@@ -873,7 +877,7 @@ static void outputTileData(UniqueTiles const &tiles) {
 	File output;
 	if (!output.open(options.output, std::ios_base::out | std::ios_base::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", output.c_str(options.output), strerror(errno));
+		fatal("Failed to create \"%s\": %s", output.display_name(options.output), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 
@@ -913,7 +917,7 @@ static void outputTilemap(std::vector<AttrmapEntry> const &attrmap) {
 	File output;
 	if (!output.open(options.tilemap, std::ios_base::out | std::ios_base::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", output.c_str(options.tilemap), strerror(errno));
+		fatal("Failed to create \"%s\": %s", output.display_name(options.tilemap), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 
@@ -929,7 +933,7 @@ static void
 	File output;
 	if (!output.open(options.attrmap, std::ios_base::out | std::ios_base::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", output.c_str(options.attrmap), strerror(errno));
+		fatal("Failed to create \"%s\": %s", output.display_name(options.attrmap), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 
@@ -950,7 +954,7 @@ static void
 	File output;
 	if (!output.open(options.palmap, std::ios_base::out | std::ios_base::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", output.c_str(options.palmap), strerror(errno));
+		fatal("Failed to create \"%s\": %s", output.display_name(options.palmap), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 

src/gfx/reverse.cpp

@@ -31,7 +31,7 @@
 static std::vector<uint8_t> readInto(std::string const &path) {
 	File file;
 	if (!file.open(path, std::ios::in | std::ios::binary)) {
-		fatal("Failed to open \"%s\": %s", file.c_str(path), strerror(errno));
+		fatal("Failed to open \"%s\": %s", file.display_name(path), strerror(errno));
 	}
 	std::vector<uint8_t> data(128 * 16); // Begin with some room pre-allocated
 
@@ -207,7 +207,9 @@ void reverse() {
 	if (!options.palettes.empty()) {
 		File file;
 		if (!file.open(options.palettes, std::ios::in | std::ios::binary)) {
-			fatal("Failed to open \"%s\": %s", file.c_str(options.palettes), strerror(errno));
+			fatal(
+			    "Failed to open \"%s\": %s", file.display_name(options.palettes), strerror(errno)
+			);
 		}
 
 		palettes.clear();
@@ -478,12 +480,12 @@ void reverse() {
 	File pngFile;
 	if (!pngFile.open(options.input, std::ios::out | std::ios::binary)) {
 		// LCOV_EXCL_START
-		fatal("Failed to create \"%s\": %s", pngFile.c_str(options.input), strerror(errno));
+		fatal("Failed to create \"%s\": %s", pngFile.display_name(options.input), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
 	png_structp png = png_create_write_struct(
 	    PNG_LIBPNG_VER_STRING,
-	    const_cast<char *>(pngFile.c_str(options.input)),
+	    const_cast<char *>(pngFile.display_name(options.input)),
 	    pngError,
 	    pngWarning
 	);