Fix code to release read-write buffers after writes are completed. Fixes

 #69.

Related to libuv/libuv#1072

code/multi-echo-server/worker.c

@@ -8,6 +8,17 @@
 uv_loop_t *loop;
 uv_pipe_t queue;
 
+typedef struct {
+    uv_write_t req;
+    uv_buf_t buf;
+} write_req_t;
+
+void free_write_req(uv_write_t *req) {
+    write_req_t *wr = (write_req_t*) req;
+    free(wr->buf.base);
+    free(wr);
+}
+
 void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
   buf->base = malloc(suggested_size);
   buf->len = suggested_size;
@@ -17,20 +28,23 @@ void echo_write(uv_write_t *req, int status) {
     if (status) {
         fprintf(stderr, "Write error %s\n", uv_err_name(status));
     }
-    free(req);
+    free_write_req(req);
 }
 
 void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {
+    if (nread > 0) {
+        write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));
+        req->buf = uv_buf_init(buf->base, nread);
+        uv_write((uv_write_t*) req, client, &req->buf, 1, echo_write);
+        return;
+    }
+
     if (nread < 0) {
         if (nread != UV_EOF)
             fprintf(stderr, "Read error %s\n", uv_err_name(nread));
         uv_close((uv_handle_t*) client, NULL);
-        return;
     }
 
-    uv_write_t *req = (uv_write_t *) malloc(sizeof(uv_write_t));
-    uv_buf_t wrbuf = uv_buf_init(buf->base, nread);
-    uv_write(req, client, &wrbuf, 1, echo_write);
     free(buf->base);
 }
 

code/pipe-echo-server/main.c

@@ -5,6 +5,17 @@
 
 uv_loop_t *loop;
 
+typedef struct {
+    uv_write_t req;
+    uv_buf_t buf;
+} write_req_t;
+
+void free_write_req(uv_write_t *req) {
+    write_req_t *wr = (write_req_t*) req;
+    free(wr->buf.base);
+    free(wr);
+}
+
 void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
   buf->base = malloc(suggested_size);
   buf->len = suggested_size;
@@ -14,20 +25,23 @@ void echo_write(uv_write_t *req, int status) {
     if (status < 0) {
         fprintf(stderr, "Write error %s\n", uv_err_name(status));
     }
-    free(req);
+    free_write_req(req);
 }
 
 void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {
+    if (nread > 0) {
+        write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));
+        req->buf = uv_buf_init(buf->base, nread);
+        uv_write((uv_write_t*) req, client, &req->buf, 1, echo_write);
+        return;
+    }
+
     if (nread < 0) {
         if (nread != UV_EOF)
             fprintf(stderr, "Read error %s\n", uv_err_name(nread));
         uv_close((uv_handle_t*) client, NULL);
-        return;
     }
 
-    uv_write_t *req = (uv_write_t *) malloc(sizeof(uv_write_t));
-    uv_buf_t wrbuf = uv_buf_init(buf->base, nread);
-    uv_write(req, client, &wrbuf, 1, echo_write);
     free(buf->base);
 }
 

code/tcp-echo-server/main.c

@@ -9,6 +9,17 @@
 uv_loop_t *loop;
 struct sockaddr_in addr;
 
+typedef struct {
+    uv_write_t req;
+    uv_buf_t buf;
+} write_req_t;
+
+void free_write_req(uv_write_t *req) {
+    write_req_t *wr = (write_req_t*) req;
+    free(wr->buf.base);
+    free(wr);
+}
+
 void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
     buf->base = (char*) malloc(suggested_size);
     buf->len = suggested_size;
@@ -18,22 +29,23 @@ void echo_write(uv_write_t *req, int status) {
     if (status) {
         fprintf(stderr, "Write error %s\n", uv_strerror(status));
     }
-    free(req);
+    free_write_req(req);
 }
 
 void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {
+    if (nread > 0) {
+        write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));
+        req->buf = uv_buf_init(buf->base, nread);
+        uv_write((uv_write_t*) req, client, &req->buf, 1, echo_write);
+        return;
+    }
     if (nread < 0) {
         if (nread != UV_EOF)
             fprintf(stderr, "Read error %s\n", uv_err_name(nread));
         uv_close((uv_handle_t*) client, NULL);
-    } else if (nread > 0) {
-        uv_write_t *req = (uv_write_t *) malloc(sizeof(uv_write_t));
-        uv_buf_t wrbuf = uv_buf_init(buf->base, nread);
-        uv_write(req, client, &wrbuf, 1, echo_write);
     }
 
-    if (buf->base)
-        free(buf->base);
+    free(buf->base);
 }
 
 void on_new_connection(uv_stream_t *server, int status) {

code/uvtee/main.c

@@ -54,6 +54,7 @@ void read_stdin(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf) {
         write_data((uv_stream_t *)&file_pipe, nread, *buf, on_file_write);
     }
 
+    // OK to free buffer as write_data copies it.
     if (buf->base)
         free(buf->base);
 }