Allow reading/writing generic message types, not just tasks. (#24)

* Allow reading/writing generic message types, not just tasks.

* Allow messages of length 0 to be read/written, and handle closed sockets.

* Address comments.

* Simplify accept_client.

* Allow ports to be reused in bind_ipc_sock.

test/io_tests.c

@@ -20,20 +20,23 @@ TEST ipc_socket_test(void) {
     close(socket_fd);
     socket_fd = connect_ipc_sock(socket_pathname);
     ASSERT(socket_fd >= 0);
-    write_string(socket_fd, test_string);
-    write_bytes(socket_fd, (uint8_t *) test_bytes, strlen(test_bytes));
+    write_log_message(socket_fd, test_string);
+    write_message(socket_fd, LOG_MESSAGE, strlen(test_bytes),
+                  (uint8_t *) test_bytes);
     close(socket_fd);
     exit(0);
   } else {
     int client_fd = accept_client(socket_fd);
     ASSERT(client_fd >= 0);
-    char *message = read_string(client_fd);
+    char *message = read_log_message(client_fd);
     ASSERT(message != NULL);
     ASSERT_STR_EQ(test_string, message);
     free(message);
+    int64_t type;
     int64_t len;
     uint8_t *bytes;
-    read_bytes(client_fd, &bytes, &len);
+    read_message(client_fd, &type, &len, &bytes);
+    ASSERT(type == LOG_MESSAGE);
     ASSERT(memcmp(test_bytes, bytes, len) == 0);
     free(bytes);
     close(client_fd);

test/redis_tests.c

@@ -45,10 +45,10 @@ TEST redis_socket_test(void) {
 
   int client_fd = connect_ipc_sock(socket_pathname);
   ASSERT(client_fd >= 0);
-  write_formatted_string(client_fd, test_set_format, test_key, test_value);
+  write_formatted_log_message(client_fd, test_set_format, test_key, test_value);
 
   int server_fd = accept_client(socket_fd);
-  char *cmd = read_string(server_fd);
+  char *cmd = read_log_message(server_fd);
   close(client_fd);
   close(server_fd);
   close(socket_fd);
@@ -69,7 +69,7 @@ TEST redis_socket_test(void) {
 
 void redis_read_callback(event_loop *loop, int fd, void *context, int events) {
   db_handle *db = context;
-  char *cmd = read_string(fd);
+  char *cmd = read_log_message(fd);
   redisAsyncCommand(db->context, async_redis_socket_test_callback, NULL, cmd,
                     db->client_id, 0);
   free(cmd);
@@ -109,7 +109,7 @@ TEST async_redis_socket_test(void) {
   int client_fd = connect_ipc_sock(socket_pathname);
   ASSERT(client_fd >= 0);
   utarray_push_back(connections, &client_fd);
-  write_formatted_string(client_fd, test_set_format, test_key, test_value);
+  write_formatted_log_message(client_fd, test_set_format, test_key, test_value);
 
   event_loop_add_file(loop, client_fd, EVENT_LOOP_READ, redis_read_callback,
                       db);
@@ -148,7 +148,7 @@ void logging_read_callback(event_loop *loop,
                            void *context,
                            int events) {
   db_handle *conn = context;
-  char *cmd = read_string(fd);
+  char *cmd = read_log_message(fd);
   redisAsyncCommand(conn->context, logging_test_callback, NULL, cmd,
                     conn->client_id, 0);
   free(cmd);

test/task_tests.c

@@ -7,6 +7,7 @@
 #include "common.h"
 #include "test/example_task.h"
 #include "task.h"
+#include "io.h"
 
 SUITE(task_tests);
 
@@ -48,8 +49,13 @@ TEST send_task(void) {
   *task_return(task, 1) = globally_unique_id();
   int fd[2];
   socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
-  write_task(fd[0], task);
-  task_spec *result = read_task(fd[1]);
+  write_message(fd[0], SUBMIT_TASK, task_size(task), task);
+  int64_t type;
+  int64_t length;
+  uint8_t *message;
+  read_message(fd[1], &type, &length, &message);
+  task_spec *result = (task_spec *) message;
+  ASSERT(type == SUBMIT_TASK);
   ASSERT(memcmp(task, result, task_size(task)) == 0);
   ASSERT(memcmp(task, result, task_size(result)) == 0);
   free(task);