From 6ed78636a5fc40eafbaf31960460b5df0b14fc64 Mon Sep 17 00:00:00 2001
From: Simon Gellis <simongellis@gmail.com>
Date: Mon, 7 Oct 2024 21:20:01 -0400
Subject: [PATCH] Pretend to run the emulator

---
 include/request.h |  2 ++
 main.c            | 14 +++++++++++---
 request.c         | 11 +++++++++--
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/include/request.h b/include/request.h
index 399d58f..c5f2603 100644
--- a/include/request.h
+++ b/include/request.h
@@ -22,6 +22,7 @@ typedef enum rdb_read_state_t {
 
 typedef struct RdbRequest {
     int connfd;
+    bool blocking;
     struct Buffer {
         char buf[INBUF_LEN];
         size_t len;
@@ -36,6 +37,7 @@ typedef struct RdbRequest {
 
 void rdb_request_init(RdbRequest *req, int connfd, char *cmd, size_t cmdlen);
 void rdb_request_reset(RdbRequest *req);
+void rdb_request_set_blocking(RdbRequest *req, bool blocking);
 rdb_read_result_t rdb_request_read(RdbRequest *req, size_t *len);
 
 #endif
\ No newline at end of file
diff --git a/main.c b/main.c
index 201c28d..ce21ea6 100644
--- a/main.c
+++ b/main.c
@@ -78,10 +78,11 @@ const uint32_t SYSTEM_REGISTERS[] = {
 
 const uint32_t PC_INDEX = 32 + 13;
 
-int handle_command(RdbClient *client, CommandBuf *cmd, VB *sim) {
+int handle_command(RdbClient *client, CommandBuf *cmd, VB *sim, bool *running) {
     rdb_client_begin_packet(client);
 
     if (cmd_match_only_str(cmd, "\x03")) {
+        *running = false;
         rdb_client_write_str(client, "T05thread:p1.t1;threads:p1.t1");
         return rdb_client_send_packet(client);
     }
@@ -183,6 +184,7 @@ int handle_command(RdbClient *client, CommandBuf *cmd, VB *sim) {
     }
     if (cmd_match_only_str(cmd, "c")) {
         printf("running until we hit a breakpoint or the server stops us\n");
+        *running = true;
         return 0;
     }
     if (cmd_match_only_str(cmd, "?")) {
@@ -224,6 +226,8 @@ int server(int connfd, VB *sim) {
     rdb_request_init(&req, connfd, buf, BUFLEN);
     rdb_client_init(&client, connfd);
 
+    bool running = false;
+
     while (1) {
         rdb_read_result_t result = rdb_request_read(&req, &len);
         if (result == read_result_error) {
@@ -232,7 +236,10 @@ int server(int connfd, VB *sim) {
             printf("client has disconnected\n");
             return 0;
         } else if (result == read_result_pending) {
-            // TODO: should run the emulator while we wait
+            if (running) {
+                printf("pretend the emulator is running now\n");
+                sleep(1);
+            }
             continue;
         } else {
             printf("received command \"%.*s\"\n", (int) len, buf);
@@ -240,10 +247,11 @@ int server(int connfd, VB *sim) {
             CommandBuf cmd;
             cmd.buf = buf;
             cmd.len = len;
-            int res = handle_command(&client, &cmd, sim);
+            int res = handle_command(&client, &cmd, sim, &running);
             if (res != 0) {
                 return res;
             }
+            rdb_request_set_blocking(&req, !running);
             rdb_request_reset(&req);
         }
 
diff --git a/request.c b/request.c
index ca66cf8..f17d625 100644
--- a/request.c
+++ b/request.c
@@ -2,12 +2,14 @@
 #include <hex.h>
 #include <request.h>
 #include <stdio.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 void rdb_request_init(RdbRequest *req, int connfd, char *cmd, size_t cmdlen) {
     req->connfd = connfd;
     req->cmd = cmd;
     req->cmdlen = cmdlen;
+    req->blocking = true;
     rdb_request_reset(req);
 }
 
@@ -19,14 +21,19 @@ void rdb_request_reset(RdbRequest *req) {
     req->chk = 0;
 }
 
+void rdb_request_set_blocking(RdbRequest *req, bool blocking) {
+    req->blocking = blocking;
+}
+
 static rdb_read_result_t read_char(RdbRequest *req, char *in) {
     if (req->inbuf.index >= req->inbuf.len) {
-        ssize_t inlen = read(req->connfd, req->inbuf.buf, INBUF_LEN);
+        int flags = req->blocking ? 0 : MSG_DONTWAIT;
+        ssize_t inlen = recv(req->connfd, req->inbuf.buf, INBUF_LEN, flags);
         if (inlen == 0) {
             return read_result_disconnected;
         }
         if (inlen < 0) {
-            if (errno == EAGAIN) {
+            if (errno == EAGAIN || errno == EWOULDBLOCK) {
                 return read_result_pending;
             } else {
                 perror("could not read incoming packet");