initial commit

main.cc

@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * (c) 2025, Konstantin Demin
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" {
+	#include <unistd.h>
+}
+
+#include "overlay.hh"
+
+static
+void usage(int retcode = 0)
+{
+	static const char usage_msg[] =
+	"overlaydirs 0.0.1\n"
+	"Usage:\n"
+	"  overlaydirs --help\n"
+	"    show this message\n"
+	"  overlaydirs --list [--no-sort|--zero] <source directory> [..<source directory>]\n"
+	// TODO: shell-escape mode
+	/* "  overlaydirs --list [--no-sort|--zero|--escape] <source directory> [..<source directory>]\n" */
+	"    list entries\n"
+	"  overlaydirs --merge <target directory> <source directory> [..<source directory>]\n"
+	"    symlinks entries into <target directory>\n"
+	"\n"
+	"  --no-sort  - don't sort entries\n"
+	"  --zero     - separate entries with NUL instead of LF\n"
+	// TODO: shell-escape mode
+	/*
+	"  --escape   - shell-escape strings\n"
+	"\n"
+	"Notes:\n"
+	" - flags \"--zero\" and \"--escape\" are mutually exclusive.\n"
+	*/
+	;
+
+	(void) write(STDERR_FILENO, usage_msg, sizeof(usage_msg));
+
+	exit(retcode);
+}
+
+static int main_list(int argc, char * argv[]);
+static int main_merge(int argc, char * argv[]);
+
+int main(int argc, char * argv[])
+{
+	if (argc < 2) usage(0);
+
+	if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0))
+		usage(0);
+	else if (strcmp(argv[1], "--list") == 0)
+		return main_list(argc, argv);
+	else if (strcmp(argv[1], "--merge") == 0)
+		return main_merge(argc, argv);
+	else
+		usage(EINVAL);
+
+	return 0;
+}
+
+static int main_list(int argc, char * argv[])
+{
+	if (argc < 3) usage(EINVAL);
+
+	print_mode print_m = print_mode::_default;
+	sort_mode sort_m = sort_mode::_default;
+
+	int arg_start = 2;
+	while (arg_start < argc) {
+		char * _arg = argv[arg_start];
+
+		if (strncmp(_arg, "--", 2) != 0) break;
+
+		if (strcmp(_arg, "--") == 0) {
+			arg_start++;
+			break;
+		}
+		else if (strcmp(_arg, "--no-sort") == 0) {
+			arg_start++;
+			if (sort_m != sort_mode::_default) {
+				(void) fprintf(stderr, "overlaydirs: no-sort mode already set\n");
+			}
+			sort_m = sort_mode::none;
+		}
+		else if (strcmp(_arg, "--zero") == 0) {
+			arg_start++;
+			if (print_m != print_mode::_default) {
+				(void) fprintf(stderr, "overlaydirs: output mode already set\n");
+			}
+			print_m = print_mode::zero;
+		}
+		// TODO
+		/*
+		else if (strcmp(_arg, "--escape") == 0) {
+			arg_start++;
+			if (print_m != print_mode::_default) {
+				(void) fprintf(stderr, "overlaydirs: output mode already set\n");
+			}
+			print_m = print_mode::shell_escape;
+		}
+		*/
+		else {
+			(void) fprintf(stderr, "overlaydirs: unknown option \"%s\"\n", _arg);
+			// nevertheless, continue and try argument as a directory
+			break;
+		}
+	}
+
+	auto roots = std::vector<ovl_dirspec_t>();
+	for (int i = arg_start; i < argc; i++) {
+		ovl_dirspec_t t;
+		if (!arg_to_rootspec(argv[i], &t, ovl_rootspec_flags::relative)) continue;
+		roots.push_back(t);
+	}
+	if (roots.empty()) {
+		(void) fprintf(stderr, "overlaydirs: no usable sources found\n");
+		return EINVAL;
+	}
+
+	auto ovl = process_overlay(roots, sort_m);
+	// not needed anymore
+	roots.clear();
+	roots.shrink_to_fit();
+
+	list_overlay(ovl, print_m);
+	return 0;
+}
+
+static int main_merge(int argc, char * argv[])
+{
+	if (argc < 4) usage(EINVAL);
+
+	ovl_dirspec_t target;
+	if (!arg_to_rootspec(argv[2], &target, ovl_rootspec_flags::relative)) {
+		(void) fprintf(stderr, "overlaydirs: not a directory: \"%s\"\n", argv[2]);
+		return EINVAL;
+	}
+	if (!is_empty_dir(target.fd)) {
+		(void) fprintf(stderr, "overlaydirs: target directory is not empty\n");
+		return EEXIST;
+	}
+
+	auto roots = std::vector<ovl_dirspec_t>();
+	for (int i = 3; i < argc; i++) {
+		ovl_dirspec_t t;
+		if (!arg_to_rootspec(argv[i], &t)) continue;
+		roots.push_back(t);
+	}
+	if (roots.empty()) {
+		(void) fprintf(stderr, "overlaydirs: no usable sources found\n");
+		return EINVAL;
+	}
+
+	auto ovl = process_overlay(roots);
+	// not needed anymore
+	roots.clear();
+	roots.shrink_to_fit();
+
+	int rv = merge_overlay(ovl, target);
+	if (rv == -1) {
+		(void) fprintf(stderr, "overlaydirs: target directory is not empty\n");
+		return EEXIST;
+	}
+
+	return rv;
+}