X-Git-Url: https://git.sesse.net/?p=plocate;a=blobdiff_plain;f=io_uring_engine.h;h=bcb10581cd84c716c0d109d3f266446d141167e5;hp=c165a40f51df19f2054ff6210d526e52c2e3e3fb;hb=HEAD;hpb=2fcf8490a3a7a2e1d434f33383b5d33a0bc3ac03

diff --git a/io_uring_engine.h b/io_uring_engine.h
index c165a40..bcb1058 100644
--- a/io_uring_engine.h
+++ b/io_uring_engine.h
@@ -7,6 +7,7 @@
 #include <string_view>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <linux/stat.h>
 
 struct io_uring_sqe;
 #ifndef WITHOUT_URING
@@ -17,17 +18,24 @@ class IOUringEngine {
 public:
 	IOUringEngine(size_t slop_bytes);
 	void submit_read(int fd, size_t len, off_t offset, std::function<void(std::string_view)> cb);
+
+	// NOTE: We just do the stat() to get the data into the dentry cache for fast access,
+	// or to check whether the file exists. Thus, the callback has only an OK/not OK boolean.
+	void submit_stat(const char *path, std::function<void(bool ok)> cb);
+	bool get_supports_stat() { return supports_stat; }
+
 	void finish();
 	size_t get_waiting_reads() const { return pending_reads + queued_reads.size(); }
 
 private:
 #ifndef WITHOUT_URING
 	void submit_read_internal(io_uring_sqe *sqe, int fd, size_t len, off_t offset, std::function<void(std::string_view)> cb);
+	void submit_stat_internal(io_uring_sqe *sqe, char *path, std::function<void(bool)> cb);
 
 	io_uring ring;
 #endif
 	size_t pending_reads = 0;  // Number of requests we have going in the ring.
-	bool using_uring;
+	bool using_uring, supports_stat = false;
 	const size_t slop_bytes;
 
 	struct QueuedRead {
@@ -38,23 +46,40 @@ private:
 	};
 	std::queue<QueuedRead> queued_reads;
 
+	struct QueuedStat {
+		char *pathname;  // Owned by us.
+		std::function<void(bool)> cb;
+	};
+	std::queue<QueuedStat> queued_stats;
+
+	enum Op { OP_READ,
+	          OP_STAT };
+
 	struct PendingRead {
-		void *buf;
-		size_t len;
-		std::function<void(std::string_view)> cb;
+		Op op;
 
-		// For re-submission.
-		int fd;
-		off_t offset;
-		iovec iov;
+		std::function<void(std::string_view)> read_cb;
+		std::function<void(bool)> stat_cb;
+
+		union {
+			struct {
+				void *buf;
+				size_t len;
+
+				// For re-submission.
+				int fd;
+				off_t offset;
+				iovec iov;
+			} read;
+			struct {
+				char *pathname;
+				struct statx *buf;
+			} stat;
+		};
 	};
 
 	// 256 simultaneous requests should be ample, for slow and fast media alike.
 	static constexpr size_t queue_depth = 256;
 };
 
-// A wrapper around pread() that returns an incomplete read.
-// Always synchronous (no io_uring).
-void complete_pread(int fd, void *ptr, size_t len, off_t offset);
-
 #endif  // !defined(IO_URING_ENGINE_H)