xmldoc: Improve xmldoc wrapping of 'core show ...' output.

Previously, the wrapping did both lookahead and lookback, which,
together with color escape sequences, caused some lines to be wrapped
way earlier than other lines.  This led to inconsistent output.

This simplifies the wrapping code and makes it more sane: if maxcolumns
is hit, we simply jump back to the last space and wrap there.

ASTERISK-25527 #close

Change-Id: I56d01c6f9a812642b1b05535c98d4db48d17c957

1 files changed, 33 insertions, 131 deletions

diff --git a/main/xmldoc.c b/main/xmldoc.c
index 86c3f6512..1e3d36860 100644
--- a/main/xmldoc.c
+++ b/main/xmldoc.c
@@ -45,18 +45,9 @@ ASTERISK_REGISTER_FILE()
 /*! \brief Default documentation language. */
 static const char default_documentation_language[] = "en_US";
 
-/*!
- * \brief Number of columns to print when showing the XML documentation with a
- *         'core show application/function *' CLI command. Used in text wrapping.
- */
-static const int xmldoc_text_columns = 74;
-
-/*!
- * \brief This is a value that we will use to let the wrapping mechanism move the cursor
- *         backward and forward xmldoc_max_diff positions before cutting the middle of a
- *         word, trying to find a space or a \n.
- */
-static const int xmldoc_max_diff = 5;
+/*! \brief Number of columns to print when showing the XML documentation with a
+ *         'core show application/function *' CLI command. Used in text wrapping.*/
+static const int xmldoc_text_columns = 79;
 
 /*! \brief XML documentation language. */
 static char documentation_language[6];
@@ -176,100 +167,22 @@ static void xmldoc_setpostbr(char *postbr, size_t len, const char *text)
 
 /*!
  * \internal
- * \brief Try to find a space or a break in text starting at currentpost
- *         and moving at most maxdiff positions.
- *         Helper for xmldoc_string_wrap().
- *
- * \param text Input string where it will search.
- * \param currentpos Current position within text.
- * \param maxdiff Not move more than maxdiff inside text.
- *
- * \retval 1 if a space or break is found inside text while moving.
- * \retval 0 if no space or break is found.
- */
-static int xmldoc_wait_nextspace(const char *text, int currentpos, int maxdiff)
-{
-	int i, textlen;
-
-	if (!text) {
-		return 0;
-	}
-
-	textlen = strlen(text);
-	for (i = currentpos; i < textlen; i++) {
-		if (text[i] == ESC) {
-			/* Move to the end of the escape sequence */
-			while (i < textlen && text[i] != 'm') {
-				i++;
-			}
-		} else if (text[i] == ' ' || text[i] == '\n') {
-			/* Found the next space or linefeed */
-			return 1;
-		} else if (i - currentpos > maxdiff) {
-			/* We have looked the max distance and didn't find it */
-			return 0;
-		}
-	}
-
-	/* Reached the end and did not find it */
-
-	return 0;
-}
-
-/*!
- * \internal
- * \brief Helper function for xmldoc_string_wrap().
- *    Try to found a space or a break inside text moving backward
- *    not more than maxdiff positions.
- *
- * \param text The input string where to search for a space.
- * \param currentpos The current cursor position.
- * \param maxdiff The max number of positions to move within text.
- *
- * \retval 0 If no space is found (Notice that text[currentpos] is not a space or a break)
- * \retval > 0 If a space or a break is found, and the result is the position relative to
- *  currentpos.
- */
-static int xmldoc_foundspace_backward(const char *text, int currentpos, int maxdiff)
-{
-	int i;
-
-	for (i = currentpos; i > 0; i--) {
-		if (text[i] == ' ' || text[i] == '\n') {
-			return (currentpos - i);
-		} else if (text[i] == 'm' && (text[i - 1] >= '0' || text[i - 1] <= '9')) {
-			/* give up, we found the end of a possible ESC sequence. */
-			return 0;
-		} else if (currentpos - i > maxdiff) {
-			/* give up, we can't move anymore. */
-			return 0;
-		}
-	}
-
-	/* we found the beginning of the text */
-
-	return 0;
-}
-
-/*!
- * \internal
  * \brief Justify a text to a number of columns.
  *
  * \param text Input text to be justified.
  * \param columns Number of columns to preserve in the text.
- * \param maxdiff Try to not cut a word when goinf down.
  *
  * \retval NULL on error.
  * \retval The wrapped text.
  */
-static char *xmldoc_string_wrap(const char *text, int columns, int maxdiff)
+static char *xmldoc_string_wrap(const char *text, int columns)
 {
 	struct ast_str *tmp;
 	char *ret, postbr[160];
-	int count = 1, i, backspace, needtobreak = 0, colmax, textlen;
+	int count, i, textlen, postbrlen, lastbreak;
 
 	/* sanity check */
-	if (!text || columns <= 0 || maxdiff < 0) {
+	if (!text || columns <= 0) {
 		ast_log(LOG_WARNING, "Passing wrong arguments while trying to wrap the text\n");
 		return NULL;
 	}
@@ -282,55 +195,44 @@ static char *xmldoc_string_wrap(const char *text, int columns, int maxdiff)
 
 	/* Check for blanks and tabs and put them in postbr. */
 	xmldoc_setpostbr(postbr, sizeof(postbr), text);
-	colmax = columns - xmldoc_postbrlen(postbr);
+	postbrlen = xmldoc_postbrlen(postbr);
+
+	count = 0;
+	lastbreak = 0;
 
 	textlen = strlen(text);
 	for (i = 0; i < textlen; i++) {
-		if (needtobreak || !(count % colmax)) {
-			if (text[i] == ' ') {
-				ast_str_append(&tmp, 0, "\n%s", postbr);
-				needtobreak = 0;
-				count = 1;
-			} else if (text[i] != '\n') {
-				needtobreak = 1;
-				if (xmldoc_wait_nextspace(text, i, maxdiff)) {
-					/* wait for the next space */
-					ast_str_append(&tmp, 0, "%c", text[i]);
-					continue;
-				}
-				/* Try to look backwards */
-				backspace = xmldoc_foundspace_backward(text, i, maxdiff);
-				if (backspace) {
-					needtobreak = 1;
-					ast_str_truncate(tmp, -backspace);
-					i -= backspace + 1;
-					continue;
-				}
-				ast_str_append(&tmp, 0, "\n%s", postbr);
-				needtobreak = 0;
-				count = 1;
-			}
-			/* skip blanks after a \n */
-			while (text[i] == ' ') {
-				i++;
-			}
-		}
 		if (text[i] == '\n') {
 			xmldoc_setpostbr(postbr, sizeof(postbr), &text[i] + 1);
-			colmax = columns - xmldoc_postbrlen(postbr);
-			needtobreak = 0;
-			count = 1;
-		}
-		if (text[i] == ESC) {
-			/* Ignore Escape sequences. */
+			postbrlen = xmldoc_postbrlen(postbr);
+			count = 0;
+			lastbreak = 0;
+		} else if (text[i] == ESC) {
+			/* Walk over escape sequences without counting them. */
 			do {
 				ast_str_append(&tmp, 0, "%c", text[i]);
 				i++;
 			} while (i < textlen && text[i] != 'm');
 		} else {
+			if (text[i] == ' ') {
+				lastbreak = i;
+			}
 			count++;
 		}
-		ast_str_append(&tmp, 0, "%c", text[i]);
+
+		if (count > columns) {
+			/* Seek backwards if it was at most 30 characters ago. */
+			int back = i - lastbreak;
+			if (lastbreak && back > 0 && back < 30) {
+				ast_str_truncate(tmp, -back);
+				i = lastbreak; /* go back a bit */
+			}
+			ast_str_append(&tmp, 0, "\n%s", postbr);
+			count = postbrlen;
+			lastbreak = 0;
+		} else {
+			ast_str_append(&tmp, 0, "%c", text[i]);
+		}
 	}
 
 	ret = ast_strdup(ast_str_buffer(tmp));
@@ -442,7 +344,7 @@ char *ast_xmldoc_printable(const char *bwinput, int withcolors)
 	}
 
 	/* Wrap the text, notice that string wrap will avoid cutting an ESC sequence. */
-	wrapped = xmldoc_string_wrap(ast_str_buffer(colorized), xmldoc_text_columns, xmldoc_max_diff);
+	wrapped = xmldoc_string_wrap(ast_str_buffer(colorized), xmldoc_text_columns);
 
 	ast_free(colorized);