From 0da766e50540fbb92b2cb510dab13eee054b097c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Fri, 12 Feb 2021 10:03:01 +0100
Subject: [PATCH] =?UTF-8?q?selection:=20don=E2=80=99t=20strip=20formatting?=
 =?UTF-8?q?=20C0=20control=20characters=20in=20bracketed=20paste=20mode?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

It’s ok to let the receiving end handle formatting C0 control
characters in bracketed paste mode.

In fact, we *must* let them through. Otherwise it is impossible to
paste e.g. tabs into editors and similar applications.
---
 CHANGELOG.md |  1 +
 selection.c  | 43 +++++++++++++++++++++++++------------------
 2 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d43d6f1f..8d8dc9de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -88,6 +88,7 @@
   `shift` to be pressed while used in a mouse grabbing
   application. This meant the mouse event was never seen by the
   application.
+* `BS`, `HT` and `DEL` from being stripped in bracketed paste mode.
 
 
 ### Security
diff --git a/selection.c b/selection.c
index cb625541..f5a114c8 100644
--- a/selection.c
+++ b/selection.c
@@ -1615,6 +1615,15 @@ fdm_receive(struct fdm *fdm, int fd, int events, void *data)
          */
         char *p = text;
         size_t left = count;
+
+#define skip_one()                              \
+        do {                                    \
+            ctx->decoder(ctx, p, i);            \
+            xassert(i + 1 <= left);             \
+            p += i + 1;                         \
+            left -= i + 1;                      \
+        } while (0)
+
     again:
         for (size_t i = 0; i < left; i++) {
             switch (p[i]) {
@@ -1629,33 +1638,29 @@ fdm_receive(struct fdm *fdm, int fd, int events, void *data)
             case '\r':
                 /* Convert \r\n -> \r */
                 if (!ctx->bracketed && i + 1 < left && p[i + 1] == '\n') {
-                    ctx->decoder(ctx, p, i + 1);
-
-                    xassert(i + 2 <= left);
-                    p += i + 2;
-                    left -= i + 2;
+                    i++;
+                    skip_one();
                     goto again;
                 }
                 break;
 
             /* C0 non-formatting control characters (\b \t \n \r excluded) */
             case '\x01': case '\x02': case '\x03': case '\x04': case '\x05':
-            case '\x06': case '\x07': case '\x0b': case '\x0c': case '\x0e':
-            case '\x0f': case '\x10': case '\x11': case '\x12': case '\x13':
-            case '\x14': case '\x15': case '\x16': case '\x17': case '\x18':
-            case '\x19': case '\x1a': case '\x1b': case '\x1c': case '\x1d':
-            case '\x1e': case '\x1f':
-                /* FALLTHROUGH */
+            case '\x06': case '\x07': case '\x0e': case '\x0f': case '\x10':
+            case '\x11': case '\x12': case '\x13': case '\x14': case '\x15':
+            case '\x16': case '\x17': case '\x18': case '\x19': case '\x1a':
+            case '\x1b': case '\x1c': case '\x1d': case '\x1e': case '\x1f':
+                skip_one();
+                goto again;
 
             /* Additional control characters stripped by default (but
              * configurable) in XTerm: BS, HT, DEL */
-            case '\b': case '\t': case '\x7f':
-                ctx->decoder(ctx, p, i);
-
-                xassert(i + 1 <= left);
-                p += i + 1;
-                left -= i + 1;
-                goto again;
+            case '\b': case '\t': case '\v': case '\f': case '\x7f':
+                if (!ctx->bracketed) {
+                    skip_one();
+                    goto again;
+                }
+                break;
             }
         }
 
@@ -1663,6 +1668,8 @@ fdm_receive(struct fdm *fdm, int fd, int events, void *data)
         left = 0;
     }
 
+#undef skip_one
+
 done:
     ctx->finish(ctx);
     clipboard_receive_done(fdm, ctx);