libunit-wasm: Remove the idx argument from luw_http_add_header()

This was used to specify the index of the response header being added,
starting at 0 and incrementing by one for each header.

Instead of having the programmer specify this, track it internally.

We add an extra check in luw_http_add_header() to make sure we aren't
trying to add more headers than we said with luw_http_init_headers(), if
we are, simply return.

This updates the API-C.md and the various examples and 'rusty' API
wrapper.

Suggested-by: Liam Crilly <liam@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

4 files changed, 6 insertions, 8 deletions

diff --git a/examples/c/luw-echo-request.c b/examples/c/luw-echo-request.c
index 5655c65..66c3880 100644
--- a/examples/c/luw-echo-request.c
+++ b/examples/c/luw-echo-request.c
@@ -85,8 +85,8 @@ int luw_request_handler(u8 *addr)
 	luw_http_init_headers(&ctx, 2, 0);
 
 	snprintf(clen, sizeof(clen), "%lu", luw_get_response_data_size(&ctx));
-	luw_http_add_header(&ctx, 0, "Content-Type", "text/plain");
-	luw_http_add_header(&ctx, 1, "Content-Length", clen);
+	luw_http_add_header(&ctx, "Content-Type", "text/plain");
+	luw_http_add_header(&ctx, "Content-Length", clen);
 
 	luw_http_send_headers(&ctx);
 
diff --git a/examples/c/luw-upload-reflector.c b/examples/c/luw-upload-reflector.c
index 95bc514..5abce9f 100644
--- a/examples/c/luw-upload-reflector.c
+++ b/examples/c/luw-upload-reflector.c
@@ -57,8 +57,8 @@ static int upload_reflector(luw_ctx_t *ctx)
 			 luw_get_http_content_len(ctx));
 
 		luw_http_init_headers(ctx, 2, 0);
-		luw_http_add_header(ctx, 0, "Content-Type", ct ? ct : defct);
-		luw_http_add_header(ctx, 1, "Content-Length", clen);
+		luw_http_add_header(ctx, "Content-Type", ct ? ct : defct);
+		luw_http_add_header(ctx, "Content-Length", clen);
 		luw_http_send_headers(ctx);
 	}
 
diff --git a/examples/rust/echo-request/src/lib.rs b/examples/rust/echo-request/src/lib.rs
index 3fea8d5..235ad13 100644
--- a/examples/rust/echo-request/src/lib.rs
+++ b/examples/rust/echo-request/src/lib.rs
@@ -104,10 +104,9 @@ pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
     // storing the response headers at the beginning of our shared
     // memory at offset 0.
     uwr_http_init_headers(ctx, 2, 0);
-    uwr_http_add_header(ctx, 0, "Content-Type", "text/plain");
+    uwr_http_add_header(ctx, "Content-Type", "text/plain");
     uwr_http_add_header(
         ctx,
-        1,
         "Content-Length",
         &format!("{}", uwr_get_response_data_size(ctx)),
     );
diff --git a/examples/rust/upload-reflector/src/lib.rs b/examples/rust/upload-reflector/src/lib.rs
index 01138b0..43bd1c6 100644
--- a/examples/rust/upload-reflector/src/lib.rs
+++ b/examples/rust/upload-reflector/src/lib.rs
@@ -49,10 +49,9 @@ pub fn upload_reflector(ctx: *mut luw_ctx_t) -> i32 {
         }
 
         uwr_http_init_headers(ctx, 2, 0);
-        uwr_http_add_header(ctx, 0, "Content-Type", ct);
+        uwr_http_add_header(ctx, "Content-Type", ct);
         uwr_http_add_header(
             ctx,
-            1,
             "Content-Length",
             &format!("{}", uwr_get_http_content_len(ctx)),
         );