Make -R support OSC 8 hyperlink escape sequences.

NEWS.VER

@@ -20,6 +20,8 @@
 
 * Add ctrl-W search modifier for wrapping search.
 
+* Support OSC 8 hyperlinks when -R is in effect.
+
 * g command with no number will ignore -j and put first line at top of screen.
 
 * Editing the same file under different names now creates only

cvt.c

@@ -70,6 +70,7 @@ cvt_text(odst, osrc, chpos, lenp, ops)
  {
  int src_pos = (int) (src - osrc);
  int dst_pos = (int) (dst - odst);
+ struct ansi_state *pansi;
  ch = step_char(&src, +1, src_end);
  if ((ops & CVT_BS) && ch == '\b' && dst > odst)
  {
@@ -78,13 +79,13 @@ cvt_text(odst, osrc, chpos, lenp, ops)
  dst--;
  } while (dst > odst && utf_mode &&
  !IS_ASCII_OCTET(*dst) && !IS_UTF8_LEAD(*dst));
- } else if ((ops & CVT_ANSI) && IS_CSI_START(ch))
+ } else if ((ops & CVT_ANSI) && (pansi = ansi_start(ch)) != NULL)
  {
  /* Skip to end of ANSI escape sequence. */
- src++; /* skip the CSI start char */
  while (src < src_end)
- if (!is_ansi_middle(*src++))
+ if (ansi_step(pansi, *src++) != ANSI_MID)
  break;
+ ansi_done(pansi);
  } else
  {
  /* Just copy the char to the destination buffer. */

filename.c

@@ -479,8 +479,9 @@ bin_file(f)
  } else 
  {
  LWCHAR c = step_char(&p, +1, edata);
- if (ctldisp == OPT_ONPLUS && IS_CSI_START(c))
- skip_ansi(&p, edata);
+ struct ansi_state *pansi;
+ if (ctldisp == OPT_ONPLUS && (pansi = ansi_start(c)) != NULL)
+ skip_ansi(pansi, &p, edata);
  else if (binary_char(c))
  bin_count++;
  }

less.h

@@ -383,6 +383,11 @@ struct wchar_range_table
 #define AT_BINARY (1 << 5) /* LESS*BINFMT representation */
 #define AT_HILITE (1 << 6) /* Internal highlights (e.g., for search) */
 
+/* ANSI states */
+#define ANSI_MID 1
+#define ANSI_ERR 2
+#define ANSI_END 3
+
 #if '0' == 240
 #define IS_EBCDIC_HOST 1
 #endif
@@ -529,6 +534,7 @@ struct wchar_range_table
 struct mlist;
 struct loption;
 struct hilite_tree;
+struct ansi_state;
 #include "pattern.h"
 #include "funcs.h"
 

less.nro.VER

@@ -791,17 +791,25 @@ each type of control character).
 Thus, various display problems may result,
 such as long lines being split in the wrong place.
 .IP "\-R or \-\-RAW-CONTROL-CHARS"
-Like \-r, but only ANSI "color" escape sequences are output in "raw" form.
+Like \-r, but only ANSI "color" escape sequences and OSC 8 hyperlink
+sequences are output in "raw" form.
 Unlike \-r, the screen appearance is maintained correctly,
 provided that there are no escape sequences in the file 
-other than ANSI color escape sequences.
+other than these types of escape sequences.
+For the purpose of keeping track of screen appearance,
+these escape sequences are assumed to not move the cursor.
+OSC 8 hyperlinks are sequences of the form:
+.sp
+ ESC ] 8 ; \&...\& \\7
+.sp
+The terminating sequence may be either a BEL character (\\7) 
+or the two-character sequence "ESC \\".
+.sp
 ANSI color escape sequences are sequences of the form:
 .sp
  ESC [ \&...\& m
 .sp
 where the "...\&" is zero or more color specification characters.
-For the purpose of keeping track of screen appearance,
-ANSI color escape sequences are assumed to not move the cursor.
 You can make
 .I less
 think that characters other than "m" can end ANSI color escape sequences

line.c

@@ -18,6 +18,7 @@
 static char *linebuf = NULL; /* Buffer which holds the current output line */
 static char *attr = NULL; /* Extension of linebuf to hold attributes */
 public int size_linebuf = 0; /* Size of line buffer (and attr buffer) */
+static struct ansi_state *line_ansi = NULL;
 
 static int cshift; /* Current left-shift of output line buffer */
 public int hshift; /* Desired left-shift of output line buffer */
@@ -68,6 +69,12 @@ static int mbc_buf_len = 0;
 static int mbc_buf_index = 0;
 static POSITION mbc_pos;
 
+struct ansi_state {
+ int hindex;
+ int hlink;
+ int prev_esc;
+};
+
 /*
  * Initialize from environment variables.
  */
@@ -287,8 +294,9 @@ pshift(shift)
  */
  while (shifted <= shift && from < curr)
  {
+ struct ansi_state *pansi;
  c = linebuf[from];
- if (ctldisp == OPT_ONPLUS && IS_CSI_START(c))
+ if (ctldisp == OPT_ONPLUS && (pansi = ansi_start(c)) != NULL)
  {
  /* Keep cumulative effect. */
  linebuf[to] = c;
@@ -297,9 +305,10 @@ pshift(shift)
  {
  linebuf[to] = linebuf[from];
  attr[to++] = attr[from];
- if (!is_ansi_middle(linebuf[from++]))
+ if (ansi_step(pansi, linebuf[from++]) != ANSI_MID)
  break;
- } 
+ }
+ ansi_done(pansi);
  continue;
  }
 
@@ -528,29 +537,6 @@ backc(VOID_PARAM)
  return 0;
 }
 
-/*
- * Are we currently within a recognized ANSI escape sequence?
- */
- static int
-in_ansi_esc_seq(VOID_PARAM)
-{
- char *p;
-
- /*
- * Search backwards for either an ESC (which means we ARE in a seq);
- * or an end char (which means we're NOT in a seq).
- */
- for (p = &linebuf[curr]; p > linebuf; )
- {
- LWCHAR ch = step_char(&p, -1, linebuf);
- if (IS_CSI_START(ch))
- return (1);
- if (!is_ansi_middle(ch))
- return (0);
- }
- return (0);
-}
-
 /*
  * Is a character the end of an ANSI escape sequence?
  */
@@ -582,15 +568,82 @@ is_ansi_middle(ch)
  * pp is initially positioned just after the CSI_START char.
  */
  public void
-skip_ansi(pp, limit)
+skip_ansi(pansi, pp, limit)
+ struct ansi_state *pansi;
  char **pp;
  constant char *limit;
 {
  LWCHAR c;
  do {
  c = step_char(pp, +1, limit);
- } while (*pp < limit && is_ansi_middle(c));
- /* Note that we discard final char, for which is_ansi_middle is false. */
+ } while (*pp < limit && ansi_step(pansi, c) != ANSI_MID);
+ /* Note that we discard final char, for which is_ansi_end is true. */
+}
+
+/*
+ * Determine if a character starts an ANSI escape sequence.
+ * If so, return an ansi_state struct; otherwise return NULL.
+ */
+ public struct ansi_state *
+ansi_start(ch)
+ LWCHAR ch;
+{
+ struct ansi_state *pansi;
+
+ if (!IS_CSI_START(ch))
+ return NULL;
+ pansi = ecalloc(1, sizeof(struct ansi_state));
+ pansi->hindex = 0;
+ pansi->hlink = 0;
+ pansi->prev_esc = 0;
+ return pansi;
+}
+
+/*
+ * Determine whether the next char in an ANSI escape sequence
+ * ends the sequence.
+ */
+ public int
+ansi_step(pansi, ch)
+ struct ansi_state *pansi;
+ LWCHAR ch;
+{
+ if (pansi->hlink)
+ {
+ /* Hyperlink ends with \7 or ESC-backslash. */
+ if (ch == '\7')
+ return ANSI_END;
+ if (hlink->prev_esc && ch == '\\')
+ return ANSI_END;
+ hlink->prev_esc = (ch == ESC);
+ return ANSI_MID;
+ }
+ if (pansi->hindex >= 0)
+ {
+ static char hlink_prefix[] = "]8;";
+ if (ch == hlink_prefix[pansi->hindex++])
+ {
+ if (hlink_prefix[pansi->hindex] == '\0')
+ pansi->hlink = 1;
+ return ANSI_MID;
+ }
+ pansi->hindex = -1;
+ }
+ if (is_ansi_middle(ch))
+ return ANSI_MID;
+ if (is_ansi_end(ch))
+ return ANSI_END;
+ return ANSI_ERR;
+}
+
+/*
+ * Free an ansi_state structure.
+ */
+ public void
+ansi_done(pansi)
+ struct ansi_state *pansi;
+{
+ free(pansi);
 }
 
 
@@ -637,9 +690,16 @@ store_char(ch, a, rep, pos)
  }
 #endif
 
- if (ctldisp == OPT_ONPLUS && in_ansi_esc_seq())
+ if (ctldisp == OPT_ONPLUS && line_ansi == NULL)
+ line_ansi = ansi_start(ch);
+ else if (ctldisp == OPT_ONPLUS && line_ansi != NULL)
  {
- if (!is_ansi_end(ch) && !is_ansi_middle(ch)) {
+ int a = ansi_step(line_ansi, ch);
+ if (a == ANSI_END)
+ {
+ ansi_done(line_ansi);
+ line_ansi = NULL;
+ } else if (a == ANSI_ERR) {
  /* Remove whole unrecognized sequence. */
  char *p = &linebuf[curr];
  LWCHAR bch;

version.c

@@ -889,7 +889,8 @@ v562 5/19/20 Update Unicode tables; minor doc formatting.
 v563 6/13/20 Fix crash due to realpath() incompatibility.
 v564 8/25/20 Handle realpath consistently; update docs.
 v565 11/3/20 Add ESC-U command, optimize calls to realpath().
-v566 Fix crash when reopening a file while using LESSOPEN.
+v566 11/25/20 Fix crash when reopening a file while using LESSOPEN;
+ support OSC 8 hyperlinks.
 */
 
-char version[] = "566x";
+char version[] = "566";