patch 8.1.0614: placing signs can be complicatedv8.1.0614

Problem:    Placing signs can be complicated.
Solution:   Add functions for defining and placing signs.  Introduce a group
            name to avoid different plugins using the same signs. (Yegappan
            Lakshmanan, closes #3652)

19 files changed, 2071 insertions, 285 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index afc4fe134b..f76af3848a 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -2408,6 +2408,15 @@ shellescape({string} [, {special}])
 				String	escape {string} for use as shell
 					command argument
 shiftwidth([{col}])		Number	effective value of 'shiftwidth'
+sign_define({name} [, {dict}])	Number	define or update a sign
+sign_getdefined([{name}])	List	get a list of defined signs
+sign_getplaced([{expr} [, {dict}]])
+				List	get a list of placed signs
+sign_place({id}, {group}, {name}, {expr} [, {dict}])
+				Number	place a sign
+sign_undefine([{name}])		Number	undefine a sign
+sign_unplace({group} [, {dict}])
+				Number	unplace a sign
 simplify({filename})		String	simplify filename as much as possible
 sin({expr})			Float	sine of {expr}
 sinh({expr})			Float	hyperbolic sine of {expr}
@@ -7858,7 +7867,217 @@ shiftwidth([{col}])						*shiftwidth()*
 		'vartabstop' feature. If the 'vartabstop' setting is enabled and
 		no {col} argument is given, column 1 will be assumed.
 
+sign_define({name} [, {dict}])				*sign_define()*
+		Define a new sign named {name} or modify the attributes of an
+		existing sign.  This is similar to the |:sign-define| command.
 
+		Prefix {name} with a unique text to avoid name collisions.
+		There is no {group} like with placing signs.
+
+		The {name} can be a String or a Number.  The optional {dict}
+		argument specifies the sign attributes.  The following values
+		are supported:
+		    icon	full path to the bitmap file for the sign.
+		    linehl	highlight group used for the whole line the
+				sign is placed in.
+		    text	text that is displayed when there is no icon
+				or the GUI is not being used.
+		    texthl	highlight group used for the text item
+		For an existing sign, the attributes are updated.
+
+		Returns 0 on success and -1 on failure.
+
+		Examples: >
+			call sign_define("mySign", {"text" : "=>", "texthl" :
+					\ "Error", "linehl" : "Search"})
+<
+sign_getdefined([{name}])				*sign_getdefined()*
+		Get a list of defined signs and their attributes.
+		This is similar to the |:sign-list| command.
+
+		If the {name} is not supplied, then a list of all the defined
+		signs is returned. Otherwise the attribute of the specified
+		sign is returned.
+
+		Each list item in the returned value is a dictionary with the
+		following entries:
+			icon	full path to the bitmap file of the sign
+			linehl	highlight group used for the whole line the
+				sign is placed in.
+			name	name of the sign
+			text	text that is displayed when there is no icon
+				or the GUI is not being used.
+			texthl	highlight group used for the text item
+
+		Returns an empty List if there are no signs and when {name} is
+		not found.
+
+		Examples: >
+			" Get a list of all the defined signs
+			echo sign_getdefined()
+
+			" Get the attribute of the sign named mySign
+			echo sign_getdefined("mySign")
+<
+sign_getplaced([{expr} [, {dict}]])			*sign_getplaced()*
+		Return a list of signs placed in a buffer or all the buffers.
+		This is similar to the |:sign-place-list| command.
+
+		If the optional buffer name {expr} is specified, then only the
+		list of signs placed in that buffer is returned.  For the use
+		of {expr}, see |bufname()|. The optional {dict} can contain
+		the following entries:
+			group	select only signs in this group
+			id	select sign with this identifier
+			lnum	select signs placed in this line. For the use
+				of {lnum}, see |line()|.
+		If {group} is '*', then signs in all the groups including the
+		global group are returned. If {group} is not supplied, then
+		only signs in the global group are returned.  If no arguments
+		are supplied, then signs in the global group placed in all the
+		buffers are returned.
+
+		Each list item in the returned value is a dictionary with the
+		following entries:
+			bufnr	number of the buffer with the sign
+			signs	list of signs placed in {bufnr}. Each list
+				item is a dictionary with the below listed
+				entries
+
+		The dictionary for each sign contains the following entries:
+			group	sign group. Set to '' for the global group.
+			id	identifier of the sign
+			lnum	line number where the sign is placed
+			name	name of the defined sign
+			priority	sign priority
+
+		Returns an empty list on failure.
+
+		Examples: >
+			" Get a List of signs placed in eval.c in the
+			" global group
+			echo sign_getplaced("eval.c")
+
+			" Get a List of signs in group 'g1' placed in eval.c
+			echo sign_getplaced("eval.c", {'group' : 'g1'})
+
+			" Get a List of signs placed at line 10 in eval.c
+			echo sign_getplaced("eval.c", {'lnum' : 10})
+
+			" Get sign with identifier 10 placed in a.py
+			echo sign_getplaced("a.py", {'id' : 10'})
+
+			" Get sign with id 20 in group 'g1' placed in a.py
+			echo sign_getplaced("a.py", {'group' : 'g1',
+							\  'id' : 20'})
+
+			" Get a List of all the placed signs
+			echo sign_getplaced()
+<
+							*sign_place()*
+sign_place({id}, {group}, {name}, {expr} [, {dict}])
+		Place the sign defined as {name} at line {lnum} in file {expr}
+		and assign {id} and {group} to sign.  This is similar to the
+		|:sign-place| command.
+
+		If the sign identifier {id} is zero, then a new identifier is
+		allocated.  Otherwise the specified number is used. {group} is
+		the sign group name. To use the global sign group, use an
+		empty string.  {group} functions as a namespace for {id}, thus
+		two groups can use the same IDs.
+		
+		{name} refers to a defined sign.
+		{expr} refers to a buffer name or number. For the accepted
+		values, see |bufname()|.
+
+		The optional {dict} argument supports the following entries:
+			lnum		line number in the buffer {expr} where
+					the sign is to be placed. For the
+					accepted values, see |line()|.
+			priority	priority of the sign. See
+					|sign-priority| for more information.
+
+		If the optional {dict} is not specified, then it modifies the
+		placed sign {id} in group {group} to use the defined sign
+		{name}.
+
+		Returns the sign identifier on success and -1 on failure.
+
+		Examples: >
+			" Place a sign named sign1 with id 5 at line 20 in
+			" buffer json.c
+			call sign_place(5, '', 'sign1', 'json.c',
+							\ {'lnum' : 20})
+
+			" Updates sign 5 in buffer json.c to use sign2
+			call sign_place(5, '', 'sign2', 'json.c')
+
+			" Place a sign named sign3 at line 30 in
+			" buffer json.c with a new identifier
+			let id = sign_place(0, '', 'sign3', 'json.c',
+							\ {'lnum' : 30})
+
+			" Place a sign named sign4 with id 10 in group 'g3'
+			" at line 40 in buffer json.c with priority 90
+			call sign_place(10, 'g3', 'sign4', 'json.c',
+					\ {'lnum' : 40, 'priority' : 90})
+<
+sign_undefine([{name}])					*sign_undefine()*
+		Deletes a previously defined sign {name}. This is similar to
+		the |:sign-undefine| command. If {name} is not supplied, then
+		deletes all the defined signs.
+
+		Returns 0 on success and -1 on failure.
+
+		Examples: >
+			" Delete a sign named mySign
+			call sign_undefine("mySign")
+
+			" Delete all the signs
+			call sign_undefine()
+<
+sign_unplace({group} [, {dict}])			*sign_unplace()*
+		Remove a previously placed sign in one or more buffers.  This
+		is similar to the |:sign-unplace()| command.
+
+		{group} is the sign group name. To use the global sign group,
+		use an empty string.  If {group} is set to '*', then all the
+		groups including the global group are used.
+		The signs in {group} are selected based on the entries in
+		{dict}.  The following optional entries in {dict} are
+		supported:
+			buffer	buffer name or number. See |bufname()|.
+			id	sign identifier
+		If {dict} is not supplied, then all the signs in {group} are
+		removed.
+
+		Returns 0 on success and -1 on failure.
+
+		Examples: >
+			" Remove sign 10 from buffer a.vim
+			call sign_unplace('', {'buffer' : "a.vim", 'id' : 10})
+
+			" Remove sign 20 in group 'g1' from buffer 3
+			call sign_unplace('g1', {'buffer' : 3, 'id' : 20})
+
+			" Remove all the signs in group 'g2' from buffer 10
+			call sign_unplace('g2', {'buffer' : 10})
+
+			" Remove sign 30 in group 'g3' from all the buffers
+			call sign_unplace('g3', {'id' : 30})
+
+			" Remove all the signs placed in buffer 5
+			call sign_unplace('*', {'buffer' : 5})
+
+			" Remove the signs in group 'g4' from all the buffers
+			call sign_unplace('g4')
+
+			" Remove sign 40 from all the buffers
+			call sign_unplace('*', {'id' : 40})
+
+			" Remove all the placed signs from all the buffers
+			call sign_unplace('*')
+<
 simplify({filename})					*simplify()*
 		Simplify the file name as much as possible without changing
 		the meaning.  Shortcuts (on MS-Windows) or symbolic links (on
diff --git a/runtime/doc/sign.txt b/runtime/doc/sign.txt
index bd63ea9ade..115e1faa45 100644
--- a/runtime/doc/sign.txt
+++ b/runtime/doc/sign.txt
@@ -1,4 +1,4 @@
-*sign.txt*      For Vim version 8.1.  Last change: 2016 Aug 17
+*sign.txt*      For Vim version 8.1.  Last change: 2018 Dec 21
 
 
 		  VIM REFERENCE MANUAL    by Gordon Prieur
@@ -51,6 +51,20 @@ The color of the column is set with the SignColumn group |hl-SignColumn|.
 Example to set the color: >
 
 	:highlight SignColumn guibg=darkgrey
+<
+							*sign-group*
+Each sign can be assigned to either the global group or a named group. When
+placing a sign, if a group name is not supplied, or an empty string is used,
+then the sign is placed in the global group. Otherwise the sign is placed in
+the named group. The sign identifier is unique within a group. The sign group
+allows Vim plugins to use unique signs without interfering with other plugins
+using signs.
+
+							*sign-priority*
+Each placed sign is assigned a priority value. When multiple signs are placed
+on the same line, the attributes of the sign with the highest priority is used
+independent of the sign group. The default priority for a sign is 10. The
+priority is assigned at the time of placing a sign.
 
 ==============================================================================
 2. Commands					*sign-commands* *:sig* *:sign*
@@ -69,6 +83,8 @@ comment.  If you do need that, use the |:execute| command.
 
 DEFINING A SIGN.			*:sign-define* *E255* *E160* *E612*
 
+See |sign_define()| for the equivalent Vim script function.
+
 :sign define {name} {argument}...
 		Define a new sign or set attributes for an existing sign.
 		The {name} can either be a number (all digits) or a name
@@ -106,13 +122,18 @@ DEFINING A SIGN.			*:sign-define* *E255* *E160* *E612*
 
 DELETING A SIGN						*:sign-undefine* *E155*
 
+See |sign_undefine()| for the equivalent Vim script function.
+
 :sign undefine {name}
 		Deletes a previously defined sign.  If signs with this {name}
 		are still placed this will cause trouble.
 
 
+
 LISTING SIGNS						*:sign-list* *E156*
 
+See |sign_getdefined()| for the equivalent Vim script function.
+
 :sign list	Lists all defined signs and their attributes.
 
 :sign list {name}
@@ -121,6 +142,8 @@ LISTING SIGNS						*:sign-list* *E156*
 
 PLACING SIGNS						*:sign-place* *E158*
 
+See |sign_place()| for the equivalent Vim script function.
+
 :sign place {id} line={lnum} name={name} file={fname}
 		Place sign defined as {name} at line {lnum} in file {fname}.
 							*:sign-fname*
@@ -136,6 +159,25 @@ PLACING SIGNS						*:sign-place* *E158*
 		to be done several times and making changes may not work as
 		expected).
 
+		The following optional sign attributes can be specified before
+		"file=":
+			group={group}	Place sign in sign group {group}
+			priority={prio}	Assign priority {prio} to sign
+
+		By default, the sign is placed in the global sign group.
+
+		By default, the sign is assigned a default priority of 10. To
+		assign a different priority value, use "priority={prio}" to
+		specify a value. The priority is used to determine the
+		highlight group used when multiple signs are placed on the
+		same line.
+
+		Examples: >
+			:sign place 5 line=3 name=sign1 file=a.py
+			:sign place 6 group=g2 line=2 name=sign2 file=x.py
+			:sign place 9 group=g2 priority=50 line=5
+							\ name=sign1 file=a.py
+<
 :sign place {id} line={lnum} name={name} buffer={nr}
 		Same, but use buffer {nr}.
 
@@ -146,31 +188,73 @@ PLACING SIGNS						*:sign-place* *E158*
 		This can be used to change the displayed sign without moving
 		it (e.g., when the debugger has stopped at a breakpoint).
 
+		The optional "group={group}" attribute can be used before
+		"file=" to select a sign in a particular group.
+
 :sign place {id} name={name} buffer={nr}
 		Same, but use buffer {nr}.
 
 
 REMOVING SIGNS						*:sign-unplace* *E159*
 
+See |sign_unplace()| for the equivalent Vim script function.
+
 :sign unplace {id} file={fname}
 		Remove the previously placed sign {id} from file {fname}.
 		See remark above about {fname} |:sign-fname|.
 
+:sign unplace {id} group={group} file={fname}
+		Same but remove the sign {id} in sign group {group}.
+
+:sign unplace {id} group=* file={fname}
+		Same but remove the sign {id} from all the sign groups.
+
 :sign unplace * file={fname}
 		Remove all placed signs in file {fname}.
 
+:sign unplace * group={group} file={fname}
+		Remove all placed signs in group {group} from file {fname}.
+
+:sign unplace * group=* file={fname}
+		Remove all placed signs in all the groups from file {fname}.
+
 :sign unplace {id} buffer={nr}
 		Remove the previously placed sign {id} from buffer {nr}.
 
+:sign unplace {id} group={group} buffer={nr}
+		Remove the previously placed sign {id} in group {group} from
+		buffer {nr}.
+
+:sign unplace {id} group=* buffer={nr}
+		Remove the previously placed sign {id} in all the groups from
+		buffer {nr}.
+
 :sign unplace * buffer={nr}
 		Remove all placed signs in buffer {nr}.
 
+:sign unplace * group={group} buffer={nr}
+		Remove all placed signs in group {group} from buffer {nr}.
+
+:sign unplace * group=* buffer={nr}
+		Remove all placed signs in all the groups from buffer {nr}.
+
 :sign unplace {id}
 		Remove the previously placed sign {id} from all files it
 		appears in.
 
+:sign unplace {id} group={group}
+		Remove the previously placed sign {id} in group {group} from
+		all files it appears in.
+
+:sign unplace {id} group=*
+		Remove the previously placed sign {id} in all the groups from
+		all the files it appears in.
+
 :sign unplace *
-		Remove all placed signs.
+		Remove all placed signs in the global group.
+
+:sign unplace * group=*
+		Remove all placed signs in all the groups.
 
 :sign unplace
 		Remove the placed sign at the cursor position.
@@ -178,15 +262,26 @@ REMOVING SIGNS						*:sign-unplace* *E159*
 
 LISTING PLACED SIGNS					*:sign-place-list*
 
+See |sign_getplaced()| for the equivalent Vim script function.
+
 :sign place file={fname}
 		List signs placed in file {fname}.
 		See remark above about {fname} |:sign-fname|.
 
+:sign place group={group} file={fname}
+		List signs in group {group} placed in file {fname}.
+
 :sign place buffer={nr}
 		List signs placed in buffer {nr}.
 
+:sign place group={group} buffer={nr}
+		List signs in group {group} placed in buffer {nr}.
+
 :sign place	List placed signs in all files.
 
+:sign place group={group}
+		List placed signs in all sign groups in all the files.
+
 
 JUMPING TO A SIGN					*:sign-jump* *E157*
 
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 1ad044b324..343d476a4c 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -983,6 +983,14 @@ Jobs:		    			        *job-functions*
 	job_info()		get information about a job
 	job_setoptions()	set options for a job
 
+Signs:						*sign-functions*
+	sign_define()		define or update a sign
+	sign_getdefined()	get a list of defined signs
+	sign_getplaced()	get a list of placed signs
+	sign_place()		place a sign
+	sign_undefine()		undefine a sign
+	sign_unplace()		unplace a sign
+
 Terminal window:				*terminal-functions*
 	term_start()		open a terminal window and run a job
 	term_list()		get the list of terminal buffers
diff --git a/src/alloc.h b/src/alloc.h
index 36890054fd..8babde3bd7 100644
--- a/src/alloc.h
+++ b/src/alloc.h
@@ -21,5 +21,13 @@ typedef enum {
 	aid_tagstack_items,
 	aid_tagstack_from,
 	aid_tagstack_details,
+	aid_sign_getdefined,
+	aid_sign_getplaced,
+	aid_sign_define_by_name,
+	aid_sign_getlist,
+	aid_sign_getplaced_dict,
+	aid_sign_getplaced_list,
+	aid_insert_sign,
+	aid_sign_getinfo,
 	aid_last
 } alloc_id_T;
diff --git a/src/buffer.c b/src/buffer.c
index 66068d9637..4055af904f 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -936,7 +936,7 @@ free_buffer_stuff(
     uc_clear(&buf->b_ucmds);		/* clear local user commands */
 #endif
 #ifdef FEAT_SIGNS
-    buf_delete_signs(buf);		/* delete any signs */
+    buf_delete_signs(buf, (char_u *)"*");	// delete any signs */
 #endif
 #ifdef FEAT_NETBEANS_INTG
     netbeans_file_killed(buf);
@@ -5866,25 +5866,34 @@ win_found:
 
 #if defined(FEAT_SIGNS) || defined(PROTO)
 /*
- * Insert the sign into the signlist.
+ * Insert a new sign into the signlist for buffer 'buf' between the 'prev' and
+ * 'next' signs.
  */
     static void
 insert_sign(
-    buf_T	*buf,		/* buffer to store sign in */
-    signlist_T	*prev,		/* previous sign entry */
-    signlist_T	*next,		/* next sign entry */
-    int		id,		/* sign ID */
-    linenr_T	lnum,		/* line number which gets the mark */
-    int		typenr)		/* typenr of sign we are adding */
+    buf_T	*buf,		// buffer to store sign in
+    signlist_T	*prev,		// previous sign entry
+    signlist_T	*next,		// next sign entry
+    int		id,		// sign ID
+    char_u	*group,		// sign group; NULL for global group
+    int		prio,		// sign priority
+    linenr_T	lnum,		// line number which gets the mark
+    int		typenr)		// typenr of sign we are adding
 {
     signlist_T	*newsign;
 
-    newsign = (signlist_T *)lalloc((long_u)sizeof(signlist_T), FALSE);
+    newsign = (signlist_T *)lalloc_id((long_u)sizeof(signlist_T), FALSE,
+							aid_insert_sign);
     if (newsign != NULL)
     {
 	newsign->id = id;
 	newsign->lnum = lnum;
 	newsign->typenr = typenr;
+	if (group != NULL)
+	    newsign->group = vim_strsave(group);
+	else
+	    newsign->group = NULL;
+	newsign->priority = prio;
 	newsign->next = next;
 	newsign->prev = prev;
 	if (next != NULL)
@@ -5892,15 +5901,15 @@ insert_sign(
 
 	if (prev == NULL)
 	{
-	    /* When adding first sign need to redraw the windows to create the
-	     * column for signs. */
+	    // When adding first sign need to redraw the windows to create the
+	    // column for signs.
 	    if (buf->b_signlist == NULL)
 	    {
 		redraw_buf_later(buf, NOT_VALID);
 		changed_cline_bef_curs();
 	    }
 
-	    /* first sign in signlist */
+	    // first sign in signlist
 	    buf->b_signlist = newsign;
 #ifdef FEAT_NETBEANS_INTG
 	    if (netbeans_active())
@@ -5913,50 +5922,100 @@ insert_sign(
 }
 
 /*
+ * Insert a new sign sorted by line number and sign priority.
+ */
+    static void
+insert_sign_by_lnum_prio(
+    buf_T	*buf,		// buffer to store sign in
+    signlist_T	*prev,		// previous sign entry
+    int		id,		// sign ID
+    char_u	*group,		// sign group; NULL for global group
+    int		prio,		// sign priority
+    linenr_T	lnum,		// line number which gets the mark
+    int		typenr)		// typenr of sign we are adding
+{
+    signlist_T	*sign;
+
+    // keep signs sorted by lnum and by priority: insert new sign at
+    // the proper position in the list for this lnum.
+    while (prev != NULL && prev->lnum == lnum && prev->priority <= prio)
+	prev = prev->prev;
+    if (prev == NULL)
+	sign = buf->b_signlist;
+    else
+	sign = prev->next;
+
+    insert_sign(buf, prev, sign, id, group, prio, lnum, typenr);
+}
+
+/*
+ * Returns TRUE if 'sign' is in 'group'.
+ * A sign can either be in the global group (sign->group == NULL)
+ * or in a named group. If 'group' is '*', then the sign is part of the group.
+ */
+    int
+sign_in_group(signlist_T *sign, char_u *group)
+{
+    return ((group != NULL && STRCMP(group, "*") == 0) ||
+	    (group == NULL && sign->group == NULL) ||
+	    (group != NULL && sign->group != NULL &&
+					STRCMP(group, sign->group) == 0));
+}
+
+/*
+ * Return information about a sign in a Dict
+ */
+    dict_T *
+sign_get_info(signlist_T *sign)
+{
+    dict_T	*d;
+
+    if ((d = dict_alloc_id(aid_sign_getinfo)) == NULL)
+	return NULL;
+    dict_add_number(d, "id", sign->id);
+    dict_add_string(d, "group", (sign->group == NULL) ?
+						(char_u *)"" : sign->group);
+    dict_add_number(d, "lnum", sign->lnum);
+    dict_add_string(d, "name", sign_typenr2name(sign->typenr));
+    dict_add_number(d, "priority", sign->priority);
+
+    return d;
+}
+
+/*
  * Add the sign into the signlist. Find the right spot to do it though.
  */
     void
 buf_addsign(
-    buf_T	*buf,		/* buffer to store sign in */
-    int		id,		/* sign ID */
-    linenr_T	lnum,		/* line number which gets the mark */
-    int		typenr)		/* typenr of sign we are adding */
+    buf_T	*buf,		// buffer to store sign in
+    int		id,		// sign ID
+    char_u	*group,		// sign group
+    int		prio,		// sign priority
+    linenr_T	lnum,		// line number which gets the mark
+    int		typenr)		// typenr of sign we are adding
 {
-    signlist_T	*sign;		/* a sign in the signlist */
-    signlist_T	*prev;		/* the previous sign */
+    signlist_T	*sign;		// a sign in the signlist
+    signlist_T	*prev;		// the previous sign
 
     prev = NULL;
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
+    FOR_ALL_SIGNS_IN_BUF(buf)
     {
-	if (lnum == sign->lnum && id == sign->id)
+	if (lnum == sign->lnum && id == sign->id &&
+		sign_in_group(sign, group))
 	{
+	    // Update an existing sign
 	    sign->typenr = typenr;
 	    return;
 	}
 	else if (lnum < sign->lnum)
 	{
-	    // keep signs sorted by lnum: insert new sign at head of list for
-	    // this lnum
-	    while (prev != NULL && prev->lnum == lnum)
-		prev = prev->prev;
-	    if (prev == NULL)
-		sign = buf->b_signlist;
-	    else
-		sign = prev->next;
-	    insert_sign(buf, prev, sign, id, lnum, typenr);
+	    insert_sign_by_lnum_prio(buf, prev, id, group, prio, lnum, typenr);
 	    return;
 	}
 	prev = sign;
     }
 
-    // insert new sign at head of list for this lnum
-    while (prev != NULL && prev->lnum == lnum)
-	prev = prev->prev;
-    if (prev == NULL)
-	sign = buf->b_signlist;
-    else
-	sign = prev->next;
-    insert_sign(buf, prev, sign, id, lnum, typenr);
+    insert_sign_by_lnum_prio(buf, prev, id, group, prio, lnum, typenr);
 
     return;
 }
@@ -5967,15 +6026,16 @@ buf_addsign(
  */
     linenr_T
 buf_change_sign_type(
-    buf_T	*buf,		/* buffer to store sign in */
-    int		markId,		/* sign ID */
-    int		typenr)		/* typenr of sign we are adding */
+    buf_T	*buf,		// buffer to store sign in
+    int		markId,		// sign ID
+    char_u	*group,		// sign group
+    int		typenr)		// typenr of sign we are adding
 {
-    signlist_T	*sign;		/* a sign in the signlist */
+    signlist_T	*sign;		// a sign in the signlist
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
+    FOR_ALL_SIGNS_IN_BUF(buf)
     {
-	if (sign->id == markId)
+	if (sign->id == markId && sign_in_group(sign, group))
 	{
 	    sign->typenr = typenr;
 	    return sign->lnum;
@@ -5985,6 +6045,11 @@ buf_change_sign_type(
     return (linenr_T)0;
 }
 
+/*
+ * Return the type number of the sign at line number 'lnum' in buffer 'buf'
+ * which has the attribute specifed by 'type'. Returns 0 if a sign is not found
+ * at the line number or it doesn't have the specified attribute.
+ */
     int
 buf_getsigntype(
     buf_T	*buf,
@@ -5993,7 +6058,7 @@ buf_getsigntype(
 {
     signlist_T	*sign;		/* a sign in a b_signlist */
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
+    FOR_ALL_SIGNS_IN_BUF(buf)
 	if (sign->lnum == lnum
 		&& (type == SIGN_ANY
 # ifdef FEAT_SIGN_ICONS
@@ -6008,37 +6073,51 @@ buf_getsigntype(
     return 0;
 }
 
-
+/*
+ * Delete sign 'id' in group 'group' from buffer 'buf'.
+ * If 'id' is zero, then delete all the signs in group 'group'. Otherwise
+ * delete only the specified sign.
+ * If 'group' is '*', then delete the sign in all the groups. If 'group' is
+ * NULL, then delete the sign in the global group. Otherwise delete the sign in
+ * the specified group.
+ * Returns the line number of the deleted sign. If multiple signs are deleted,
+ * then returns the line number of the last sign deleted.
+ */
     linenr_T
 buf_delsign(
-    buf_T	*buf,		/* buffer sign is stored in */
-    int		id)		/* sign id */
+    buf_T	*buf,		// buffer sign is stored in
+    int		id,		// sign id
+    char_u	*group)		// sign group
 {
-    signlist_T	**lastp;	/* pointer to pointer to current sign */
-    signlist_T	*sign;		/* a sign in a b_signlist */
-    signlist_T	*next;		/* the next sign in a b_signlist */
-    linenr_T	lnum;		/* line number whose sign was deleted */
+    signlist_T	**lastp;	// pointer to pointer to current sign
+    signlist_T	*sign;		// a sign in a b_signlist
+    signlist_T	*next;		// the next sign in a b_signlist
+    linenr_T	lnum;		// line number whose sign was deleted
 
     lastp = &buf->b_signlist;
     lnum = 0;
     for (sign = buf->b_signlist; sign != NULL; sign = next)
     {
 	next = sign->next;
-	if (sign->id == id)
+	if ((id == 0 || sign->id == id) && sign_in_group(sign, group))
+
 	{
 	    *lastp = next;
 	    if (next != NULL)
 		next->prev = sign->prev;
 	    lnum = sign->lnum;
+	    vim_free(sign->group);
 	    vim_free(sign);
-	    break;
+	    // Check whether only one sign needs to be deleted
+	    if (group == NULL || (*group != '*' && id != 0))
+		break;
 	}
 	else
 	    lastp = &sign->next;
     }
 
-    /* When deleted the last sign need to redraw the windows to remove the
-     * sign column. */
+    // When deleted the last sign need to redraw the windows to remove the
+    // sign column.
     if (buf->b_signlist == NULL)
     {
 	redraw_buf_later(buf, NOT_VALID);
@@ -6050,39 +6129,78 @@ buf_delsign(
 
 
 /*
- * Find the line number of the sign with the requested id. If the sign does
- * not exist, return 0 as the line number. This will still let the correct file
- * get loaded.
+ * Find the line number of the sign with the requested id in group 'group'. If
+ * the sign does not exist, return 0 as the line number. This will still let
+ * the correct file get loaded.
  */
     int
 buf_findsign(
-    buf_T	*buf,		/* buffer to store sign in */
-    int		id)		/* sign ID */
+    buf_T	*buf,		// buffer to store sign in
+    int		id,		// sign ID
+    char_u	*group)		// sign group
 {
-    signlist_T	*sign;		/* a sign in the signlist */
+    signlist_T	*sign;		// a sign in the signlist
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
-	if (sign->id == id)
+    FOR_ALL_SIGNS_IN_BUF(buf)
+	if (sign->id == id && sign_in_group(sign, group))
 	    return sign->lnum;
 
     return 0;
 }
 
+/*
+ * Return the sign at line 'lnum' in buffer 'buf'. Returns NULL if a sign is
+ * not found at the line.
+ */
+    static signlist_T *
+buf_getsign_at_line(
+    buf_T	*buf,		// buffer whose sign we are searching for
+    linenr_T	lnum)		// line number of sign
+{
+    signlist_T	*sign;		// a sign in the signlist
+
+    FOR_ALL_SIGNS_IN_BUF(buf)
+	if (sign->lnum == lnum)
+	    return sign;
+
+    return NULL;
+}
+
+/*
+ * Return the sign with identifier 'id' in group 'group' placed in buffer 'buf'
+ */
+    signlist_T *
+buf_getsign_with_id(
+    buf_T	*buf,		// buffer whose sign we are searching for
+    int		id,		// sign identifier
+    char_u	*group)		// sign group
+{
+    signlist_T	*sign;		// a sign in the signlist
+
+    FOR_ALL_SIGNS_IN_BUF(buf)
+	if (sign->id == id && sign_in_group(sign, group))
+	    return sign;
+
+    return NULL;
+}
+
+/*
+ * Return the identifier of the sign at line number 'lnum' in buffer 'buf'.
+ */
     int
 buf_findsign_id(
-    buf_T	*buf,		/* buffer whose sign we are searching for */
-    linenr_T	lnum)		/* line number of sign */
+    buf_T	*buf,		// buffer whose sign we are searching for
+    linenr_T	lnum)		// line number of sign
 {
-    signlist_T	*sign;		/* a sign in the signlist */
+    signlist_T	*sign;		// a sign in the signlist
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
-	if (sign->lnum == lnum)
-	    return sign->id;
+    sign = buf_getsign_at_line(buf, lnum);
+    if (sign != NULL)
+	return sign->id;
 
     return 0;
 }
 
-
 # if defined(FEAT_NETBEANS_INTG) || defined(PROTO)
 /*
  * See if a given type of sign exists on a specific line.
@@ -6095,7 +6213,7 @@ buf_findsigntype_id(
 {
     signlist_T	*sign;		/* a sign in the signlist */
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
+    FOR_ALL_SIGNS_IN_BUF(buf)
 	if (sign->lnum == lnum && sign->typenr == typenr)
 	    return sign->id;
 
@@ -6110,10 +6228,10 @@ buf_findsigntype_id(
     int
 buf_signcount(buf_T *buf, linenr_T lnum)
 {
-    signlist_T	*sign;		/* a sign in the signlist */
+    signlist_T	*sign;		// a sign in the signlist
     int		count = 0;
 
-    for (sign = buf->b_signlist; sign != NULL; sign = sign->next)
+    FOR_ALL_SIGNS_IN_BUF(buf)
 	if (sign->lnum == lnum)
 	    if (sign_get_image(sign->typenr) != NULL)
 		count++;
@@ -6123,28 +6241,39 @@ buf_signcount(buf_T *buf, linenr_T lnum)
 #  endif /* FEAT_SIGN_ICONS */
 # endif /* FEAT_NETBEANS_INTG */
 
-
 /*
- * Delete signs in buffer "buf".
+ * Delete signs in group 'group' in buffer "buf". If 'group' is '*', then
+ * delete all the signs.
  */
     void
-buf_delete_signs(buf_T *buf)
+buf_delete_signs(buf_T *buf, char_u *group)
 {
+    signlist_T	*sign;
+    signlist_T	**lastp;	// pointer to pointer to current sign
     signlist_T	*next;
 
-    /* When deleting the last sign need to redraw the windows to remove the
-     * sign column. Not when curwin is NULL (this means we're exiting). */
+    // When deleting the last sign need to redraw the windows to remove the
+    // sign column. Not when curwin is NULL (this means we're exiting).
     if (buf->b_signlist != NULL && curwin != NULL)
     {
 	redraw_buf_later(buf, NOT_VALID);
 	changed_cline_bef_curs();
     }
 
-    while (buf->b_signlist != NULL)
+    lastp = &buf->b_signlist;
+    for (sign = buf->b_signlist; sign != NULL; sign = next)
     {
-	next = buf->b_signlist->next;
-	vim_free(buf->b_signlist);
-	buf->b_signlist = next;
+	next = sign->next;
+	if (sign_in_group(sign, group))
+	{
+	    *lastp = next;
+	    if (next != NULL)
+		next->prev = sign->prev;
+	    vim_free(sign->group);
+	    vim_free(sign);
+	}
+	else
+	    lastp = &sign->next;
     }
 }
 
@@ -6158,18 +6287,19 @@ buf_delete_all_signs(v