Improve fsearch

1. Fix fsearch: File were never closed and in larger directory trees we reached the maximum open file limit
2. Improve fsearch: add a semaphore to limit the concurrent requests

apps/fsearch/fsearch.cpp

@@ -15,6 +15,7 @@
 #include "CountingPrivateSemaphore.hpp"
 #include "Fiber.hpp"
 #include "Runtime.hpp"
+#include "Semaphore.hpp"
 #include "emper.hpp"
 #include "io.hpp"
 
@@ -25,7 +26,13 @@ namespace fs = std::filesystem;
 const char* needle;
 size_t needle_len;
 
+emper::Semaphore* max_running;
+
 void search(const std::string& path) {
+	if (max_running) {
+		max_running->acquire();
+	}
+
 	int fd = emper::io::openAndWait(path.c_str(), O_RDONLY);
 	if (fd < 0) {
 		DIE_MSG_ERRNO("open failed");
@@ -38,7 +45,7 @@ void search(const std::string& path) {
 	while (bytes_read > 0) {
 		if (memmem(&buf[0], bytes_read, needle, needle_len)) {
 			printf("%s\n", path.c_str());
-			return;
+			goto out;
 		}
 
 		bytes_searched += bytes_read;
@@ -48,6 +55,13 @@ void search(const std::string& path) {
 	if (bytes_read < 0) {
 		DIE_MSG_ERRNO("read failed");
 	}
+
+out:
+	if (max_running) {
+		max_running->release();
+	}
+
+	emper::io::closeAndForget(fd);
 }
 
 void walk_dir() {
@@ -64,8 +78,12 @@ void walk_dir() {
 
 auto main(int argc, char* argv[]) -> int {
 	if (argc < 2) {
-		std::cerr << "Usage: " << argv[0] << " <needle>" << std::endl;
-		return EXIT_FAILURE;
+		std::cerr << "Usage: " << argv[0] << " <needle> [max fibers]" << std::endl;
+		return EXIT_SUCCESS;
+	}
+
+	if (argc == 3) {
+		max_running = new emper::Semaphore(std::stoi(argv[2]));
 	}
 
 	needle = argv[1];
@@ -77,4 +95,5 @@ auto main(int argc, char* argv[]) -> int {
 	runtime.scheduleFromAnywhere(*dirWalker);
 
 	runtime.waitUntilFinished();
+	return EXIT_SUCCESS;
 }