From 71aa496501542b9a5b3e902ccc00e2d95c2b79d5 Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Tue, 17 Jan 2023 00:16:58 +0100
Subject: [PATCH] Bindings: read from fd.

---
 zig-impl/src/bindings.zig     | 14 +++++++++++++-
 zig-impl/test-bindings/pong.c | 15 +++++++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/zig-impl/src/bindings.zig b/zig-impl/src/bindings.zig
index d677140..730223d 100644
--- a/zig-impl/src/bindings.zig
+++ b/zig-impl/src/bindings.zig
@@ -32,6 +32,7 @@ export fn ipc_context_deinit (ctx: *Context) callconv(.C) void {
 
 export fn ipc_write (ctx: *Context, servicefd: i32, mcontent: [*]const u8, mlen: u32) i32 {
 
+    // TODO: better default length.
     var buffer: [100000]u8 = undefined;
     var fba = std.heap.FixedBufferAllocator.init(&buffer);
 
@@ -40,8 +41,19 @@ export fn ipc_write (ctx: *Context, servicefd: i32, mcontent: [*]const u8, mlen:
     return 0;
 }
 
+export fn ipc_read_fd (ctx: *Context, fd: i32, buffer: [*]u8, buflen: *usize) i32 {
+    var m = ctx.read_fd (fd) catch {return -1;} orelse return -2;
+    if (m.payload.len > buflen.*) return -3;
+    buflen.* = m.payload.len;
+
+    var fbs = std.io.fixedBufferStream(buffer[0..buflen.*]);
+    var writer = fbs.writer();
+    _ = writer.write(m.payload) catch return -4;
+
+    return 0;
+}
+
 // pub fn schedule (ctx: *Context, m: Message) !void
-// pub fn read_fd (ctx: *Context, fd: i32) !?Message
 // pub fn read (ctx: *Context, index: usize) !?Message
 // 
 // pub fn wait_event(ctx: *Context) !Event
diff --git a/zig-impl/test-bindings/pong.c b/zig-impl/test-bindings/pong.c
index 05a2788..0cb56b6 100644
--- a/zig-impl/test-bindings/pong.c
+++ b/zig-impl/test-bindings/pong.c
@@ -35,11 +35,18 @@ int main(void) {
 		return 1;
 	}
 
-#if 0
+	char message[10000];
+	unsigned int size = 10000;
+#if 1
+	ret = ipc_read_fd (ctx, servicefd, message, &size);
+
+	if (ret != 0) {
+		printf ("Cannot read from the service fd: %d.\n", ret);
+		return 1;
+	}
+#else
 	// TODO: loop over ipc_wait
 	int event_type, index, originfd = 0;
-	unsigned int size = 0;
-	char message[10000];
 	printf ("Wait for a response.\n", ret);
 	ret = ipc_wait (&event_type, &index, &originfd, &size, message);
 
@@ -47,6 +54,7 @@ int main(void) {
 		printf ("Error while waiting for an event.\n");
 		return 1;
 	}
+#endif
 
 	if (size == 0) {
 		printf ("No message returned.\n");
@@ -55,7 +63,6 @@ int main(void) {
 
 	message[size] = '\0';
 	printf ("Response: %s.\n", message);
-#endif
 
 	printf ("Deinit context\n");
 	ipc_context_deinit (ctx);