From af88c19561e4083b569a3bded26faa8347c017be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sat, 19 Mar 2022 20:13:49 +0100
Subject: [PATCH] dcs: decrqss: use a custom put() handler
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Only buffer up to two bytes, as that’s the largest DECRQSS request we
support.
---
 dcs.c | 58 ++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 36 insertions(+), 22 deletions(-)

diff --git a/dcs.c b/dcs.c
index a5feb387..7aecfb26 100644
--- a/dcs.c
+++ b/dcs.c
@@ -10,6 +10,26 @@
 #include "vt.h"
 #include "xmalloc.h"
 
+static bool
+ensure_size(struct terminal *term, size_t required_size)
+{
+    if (required_size <= term->vt.dcs.size)
+        return true;
+
+    size_t new_size = (required_size + 127) / 128 * 128;
+    xassert(new_size > 0);
+
+    uint8_t *new_data = realloc(term->vt.dcs.data, new_size);
+    if (new_data == NULL) {
+        LOG_ERRNO("failed to increase size of DCS buffer");
+        return false;
+    }
+
+    term->vt.dcs.data = new_data;
+    term->vt.dcs.size = new_size;
+    return true;
+}
+
 /* Decode hex-encoded string *inline*. NULL terminates */
 static char *
 hex_decode(const char *s, size_t len)
@@ -200,7 +220,20 @@ append_sgr_attr_n(char **reply, size_t *len, const char *attr, size_t n)
 }
 
 static void
-decrqss(struct terminal *term)
+decrqss_put(struct terminal *term, uint8_t c)
+{
+    /* Largest request we support is two bytes */
+    if (!ensure_size(term, 2))
+        return;
+
+    struct vt *vt = &term->vt;
+    if (vt->dcs.idx > 2)
+        return;
+    vt->dcs.data[vt->dcs.idx++] = c;
+}
+
+static void
+decrqss_unhook(struct terminal *term)
 {
     const uint8_t *query = term->vt.dcs.data;
     const size_t n = term->vt.dcs.idx;
@@ -387,7 +420,8 @@ dcs_hook(struct terminal *term, uint8_t final)
     case '$':
         switch (final) {
         case 'q':
-            term->vt.dcs.unhook_handler = &decrqss;
+            term->vt.dcs.put_handler = &decrqss_put;
+            term->vt.dcs.unhook_handler = &decrqss_unhook;
             break;
         }
         break;
@@ -418,26 +452,6 @@ dcs_hook(struct terminal *term, uint8_t final)
     }
 }
 
-static bool
-ensure_size(struct terminal *term, size_t required_size)
-{
-    if (required_size <= term->vt.dcs.size)
-        return true;
-
-    size_t new_size = (required_size + 127) / 128 * 128;
-    xassert(new_size > 0);
-
-    uint8_t *new_data = realloc(term->vt.dcs.data, new_size);
-    if (new_data == NULL) {
-        LOG_ERRNO("failed to increase size of DCS buffer");
-        return false;
-    }
-
-    term->vt.dcs.data = new_data;
-    term->vt.dcs.size = new_size;
-    return true;
-}
-
 void
 dcs_put(struct terminal *term, uint8_t c)
 {