From fbb4db8a83ecbb2ba7a4134ff7162cacbe4c405f Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 13 Jul 2018 17:13:59 +0530
Subject: [PATCH] Allocate talk data on the heap

Most users will talk to 0, 1, 2 peers simultaneously at the most,
so allocate memory for them dynamically.
---
 kitty/child-monitor.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/kitty/child-monitor.c b/kitty/child-monitor.c
index bb8fa336a..3a5f9e911 100644
--- a/kitty/child-monitor.c
+++ b/kitty/child-monitor.c
@@ -1065,8 +1065,6 @@ io_loop(void *data) {
 
 // {{{ Talk thread functions
 
-#define MAX_PEERS 256
-
 typedef struct {
     char *data;
     size_t capacity, used;
@@ -1085,15 +1083,18 @@ static PeerWriteData empty_pwd = {.fd = -1, 0};
 
 typedef struct {
     size_t num_listen_fds, num_talk_fds, num_reads, num_writes, num_queued_writes;
-    struct pollfd fds[MAX_PEERS + 1];
-    PeerReadData reads[MAX_PEERS + 1];
-    PeerWriteData writes[MAX_PEERS + 1];
-    PeerWriteData queued_writes[MAX_PEERS + 1];
+    size_t fds_capacity, reads_capacity, writes_capacity, queued_writes_capacity;
+    struct pollfd *fds;
+    PeerReadData *reads;
+    PeerWriteData *writes;
+    PeerWriteData *queued_writes;
     int wakeup_fds[2];
     pthread_mutex_t peer_lock;
 } TalkData;
 
 static TalkData talk_data = {0};
+typedef struct pollfd PollFD;
+#define PEER_LIMIT 256
 #define nuke_socket(s) { shutdown(s, SHUT_RDWR); close(s); }
 
 static inline bool
@@ -1105,12 +1106,14 @@ accept_peer(int listen_fd, bool shutting_down) {
         return false;
     }
     size_t fd_idx = talk_data.num_listen_fds + talk_data.num_talk_fds;
-    if (fd_idx < arraysz(talk_data.fds) && talk_data.num_reads < arraysz(talk_data.reads)) {
+    if (fd_idx < PEER_LIMIT && talk_data.reads_capacity < PEER_LIMIT) {
+        ensure_space_for(&talk_data, fds, PollFD, fd_idx + 1, fds_capacity, 8, false);
         talk_data.fds[fd_idx].fd = peer; talk_data.fds[fd_idx].events = POLLIN;
+        ensure_space_for(&talk_data, reads, PeerReadData, talk_data.num_reads + 1, reads_capacity, 8, false);
         talk_data.reads[talk_data.num_reads] = empty_prd; talk_data.reads[talk_data.num_reads++].fd = peer;
         talk_data.num_talk_fds++;
     } else {
-        log_error("Too many peers want to talk, already connected to %lu ignoring one.", talk_data.num_talk_fds);
+        log_error("Too many peers want to talk, ignoring one.");
         nuke_socket(peer);
     }
     return true;
@@ -1241,8 +1244,10 @@ move_queued_writes() {
     while (talk_data.num_queued_writes) {
         PeerWriteData *src = talk_data.queued_writes + --talk_data.num_queued_writes;
         size_t fd_idx = talk_data.num_listen_fds + talk_data.num_talk_fds;
-        if (fd_idx < arraysz(talk_data.fds) && talk_data.num_writes < arraysz(talk_data.writes)) {
+        if (fd_idx < PEER_LIMIT && talk_data.num_writes < PEER_LIMIT) {
+            ensure_space_for(&talk_data, fds, PollFD, fd_idx + 1, fds_capacity, 8, false);
             talk_data.fds[fd_idx].fd = src->fd; talk_data.fds[fd_idx].events = POLLOUT;
+            ensure_space_for(&talk_data, writes, PeerWriteData, talk_data.num_writes + 1, writes_capacity, 8, false);
             talk_data.writes[talk_data.num_writes++] = *src;
             talk_data.num_talk_fds++;
         } else {
@@ -1261,6 +1266,7 @@ talk_loop(void *data) {
     set_thread_name("KittyPeerMon");
     if ((pthread_mutex_init(&talk_data.peer_lock, NULL)) != 0) { perror("Failed to create peer mutex"); return 0; }
     if (!self_pipe(talk_data.wakeup_fds)) { perror("Failed to create wakeup fds for talk thread"); return 0; }
+    ensure_space_for(&talk_data, fds, PollFD, 8, fds_capacity, 8, false);
 #define add_listener(which) \
     if (self->which > -1) { \
         talk_data.fds[talk_data.num_listen_fds].fd = self->which; talk_data.fds[talk_data.num_listen_fds++].events = POLLIN; \
@@ -1291,6 +1297,7 @@ talk_loop(void *data) {
     }
 end:
     close(talk_data.wakeup_fds[0]); close(talk_data.wakeup_fds[1]);
+    free(talk_data.fds); free(talk_data.reads); free(talk_data.writes); free(talk_data.queued_writes);
     return 0;
 }
 
@@ -1298,7 +1305,8 @@ static inline bool
 add_peer_writer(int fd, const char* msg, size_t msg_sz) {
     bool ok = false;
     peer_mutex(lock);
-    if (talk_data.num_queued_writes < arraysz(talk_data.queued_writes)) {
+    if (talk_data.num_queued_writes < PEER_LIMIT) {
+        ensure_space_for(&talk_data, queued_writes, PeerWriteData, talk_data.num_queued_writes + 1, queued_writes_capacity, 8, false);
         talk_data.queued_writes[talk_data.num_queued_writes] = empty_pwd;
         talk_data.queued_writes[talk_data.num_queued_writes].data = malloc(msg_sz);
         if (talk_data.queued_writes[talk_data.num_queued_writes].data) {