From e06b774174649fd79cd7bc8ca946879ba4829c7a Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 13 Feb 2022 17:33:13 +0530
Subject: [PATCH] Avoid double scan of output to look for escape codes

---
 kitty/line.c    | 10 ++++++----
 kitty/lineops.h |  2 +-
 kitty/screen.c  |  5 +----
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/kitty/line.c b/kitty/line.c
index 082affee5..db2942093 100644
--- a/kitty/line.c
+++ b/kitty/line.c
@@ -302,17 +302,18 @@ write_hyperlink(hyperlink_id_type hid, ANSIBuf *output) {
 }
 
 
-void
+bool
 line_as_ansi(Line *self, ANSIBuf *output, const GPUCell** prev_cell, index_type start_at, index_type stop_before, char_type prefix_char) {
 #define ENSURE_SPACE(extra) ensure_space_for(output, buf, Py_UCS4, output->len + extra, capacity, 2048, false);
-#define WRITE_SGR(val) { ENSURE_SPACE(128); write_sgr(val, output); }
+#define WRITE_SGR(val) { ENSURE_SPACE(128); escape_code_written = true; write_sgr(val, output); }
 #define WRITE_CH(val) { ENSURE_SPACE(1); output->buf[output->len++] = val; }
-#define WRITE_HYPERLINK(val) { ENSURE_SPACE(2256); write_hyperlink(val, output); }
+#define WRITE_HYPERLINK(val) { ENSURE_SPACE(2256); escape_code_written = true; write_hyperlink(val, output); }
+    bool escape_code_written = false;
     output->len = 0;
     index_type limit = MIN(stop_before, xlimit_for_line(self));
     char_type previous_width = 0;
     if (prefix_char) { WRITE_CH(prefix_char); previous_width = wcwidth_std(prefix_char); }
-    if (limit <= start_at) return;
+    if (limit <= start_at) return escape_code_written;
 
     static const GPUCell blank_cell = { 0 };
     GPUCell *cell;
@@ -354,6 +355,7 @@ line_as_ansi(Line *self, ANSIBuf *output, const GPUCell** prev_cell, index_type
         }
         previous_width = cell->attrs.width;
     }
+    return escape_code_written;
 #undef CMP_ATTRS
 #undef CMP
 #undef WRITE_SGR
diff --git a/kitty/lineops.h b/kitty/lineops.h
index 839402b16..9c654c4fe 100644
--- a/kitty/lineops.h
+++ b/kitty/lineops.h
@@ -84,7 +84,7 @@ void line_add_combining_char(Line *, uint32_t , unsigned int );
 index_type line_url_start_at(Line *self, index_type x);
 index_type line_url_end_at(Line *self, index_type x, bool, char_type, bool);
 bool line_startswith_url_chars(Line*);
-void line_as_ansi(Line *self, ANSIBuf *output, const GPUCell**, index_type start_at, index_type stop_before, char_type prefix_char) __attribute__((nonnull));
+bool line_as_ansi(Line *self, ANSIBuf *output, const GPUCell**, index_type start_at, index_type stop_before, char_type prefix_char) __attribute__((nonnull));
 unsigned int line_length(Line *self);
 size_t cell_as_unicode(CPUCell *cell, bool include_cc, Py_UCS4 *buf, char_type);
 size_t cell_as_unicode_for_fallback(CPUCell *cell, Py_UCS4 *buf);
diff --git a/kitty/screen.c b/kitty/screen.c
index 7ddaf039c..a90ae3426 100644
--- a/kitty/screen.c
+++ b/kitty/screen.c
@@ -2479,13 +2479,10 @@ ansi_for_range(Screen *self, const Selection *sel, bool insert_newlines, bool st
                 }
             }
         }
-        line_as_ansi(line, &output, &prev_cell, xr.x, x_limit, prefix_char);
+        if (line_as_ansi(line, &output, &prev_cell, xr.x, x_limit, prefix_char)) has_escape_codes = true;
         PyObject *t = PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, output.buf, output.len);
         if (!t) return NULL;
         PyTuple_SET_ITEM(ans, i, t);
-        if (!has_escape_codes) {
-            for (size_t i = 0; i < output.len; i++) { if (output.buf[i] == 0x1b) { has_escape_codes = true; break; } }
-        }
     }
     PyObject *t = PyUnicode_FromFormat("%s%s", has_escape_codes ? "\x1b[m" : "", output.active_hyperlink_id ? "\x1b]8;;\x1b\\" : "");
     if (!t) return NULL;