launcher: compress game folders to ZAR

src/common/archive.h

@@ -5,6 +5,7 @@
 
 #include <cstdint>
 #include <filesystem>
+#include <functional>
 #include <memory>
 #include <vector>
 
@@ -45,6 +46,12 @@ private:
 // Accepts either a host archive filename or a virtual path inside the archive.
 [[nodiscard]] std::shared_ptr<ArchiveReader> OpenArchive(const std::filesystem::path& path);
 
+// Packs a host directory into a new ZArchive outside it. progress gets 0 < done <= total and
+// returns false to cancel. A failed or cancelled pack removes the partial archive.
+[[nodiscard]] bool PackArchive(const std::filesystem::path& directory,
+                               const std::filesystem::path& archive,
+                               const std::function<bool(uint64_t done, uint64_t total)>& progress);
+
 } // namespace Common
 
 #endif /* KYTY_COMMON_ARCHIVE_H_ */

src/common/archivePack.cpp

@@ -0,0 +1,84 @@
+// Kept out of archive.cpp so the statically linked emulator does not pull in the writer and the
+// zstd compressor.
+#include "common/archive.h"
+
+#include "common/stringUtils.h"
+
+#include <algorithm>
+#include <zarchive/zarchivewriter.h>
+
+namespace Common {
+
+bool PackArchive(const std::filesystem::path& directory, const std::filesystem::path& archive,
+                 const std::function<bool(uint64_t done, uint64_t total)>& progress) {
+	namespace fs = std::filesystem;
+	struct Output {
+		File file;
+		bool ok = true;
+	} output;
+	// Create the archive before walking, so a re-run started while a cancelled pack is still
+	// walking sees it exists instead of losing its archive to that pack's cleanup.
+	if (!output.file.Create(archive)) {
+		return false;
+	}
+	struct Entry {
+		fs::path path;
+		uint64_t size;
+		bool     is_file;
+	};
+	std::vector<Entry> entries;
+	uint64_t           total = 0;
+	std::error_code    error;
+	// Follow directory links, as the emulator does when it runs the folder.
+	fs::recursive_directory_iterator it(directory, fs::directory_options::follow_directory_symlink,
+	                                    error);
+	for (; !error && it != fs::end(it); it.increment(error)) {
+		const bool is_file = !it->is_directory(error);
+		const auto size    = is_file && !error ? it->file_size(error) : 0;
+		if (error) {
+			break;
+		}
+		entries.push_back({it->path(), size, is_file});
+		total += size;
+	}
+	output.ok = !error;
+	ZArchiveWriter writer(
+	    [](int32_t, void*) {},
+	    [](const void* data, size_t size, void* opaque) {
+		    auto&    out     = *static_cast<Output*>(opaque);
+		    uint32_t written = 0;
+		    out.file.Write(data, static_cast<uint32_t>(size), &written);
+		    out.ok = out.ok && written == size;
+	    },
+	    &output);
+	std::vector<uint8_t> buffer(1u << 20u);
+	uint64_t             done = 0;
+	for (size_t index = 0; output.ok && index < entries.size(); index++) {
+		const auto& entry = entries[index];
+		const auto  name  = PathToGenericString(entry.path.lexically_relative(directory));
+		File        input;
+		output.ok = entry.is_file ? writer.StartNewFile(name.c_str()) &&
+		                                input.Open(entry.path, File::Mode::Read)
+		                          : writer.MakeDir(name.c_str());
+		for (uint64_t left = entry.size; output.ok && left != 0;) {
+			uint32_t read = 0;
+			input.Read(buffer.data(), static_cast<uint32_t>(std::min<uint64_t>(left, buffer.size())),
+			           &read);
+			writer.AppendData(buffer.data(), read);
+			done += read;
+			left -= read;
+			output.ok = output.ok && read != 0 && progress(done, total);
+		}
+	}
+	if (output.ok) {
+		writer.Finalize();
+	}
+	output.ok = output.ok && output.file.Flush();
+	output.file.Close();
+	if (!output.ok) {
+		File::DeleteFile(archive);
+	}
+	return output.ok;
+}
+
+} // namespace Common