patch 8.0.1514: getting the list of changes is not easy

Problem:    Getting the list of changes is not easy.
Solution:   Add the getchangelist() function. (Yegappan Lakshmanan,
            closes #2634)

runtime/doc/eval.txt

@@ -2152,6 +2152,7 @@ getbufline({expr}, {lnum} [, {end}])
 				List	lines {lnum} to {end} of buffer {expr}
 getbufvar({expr}, {varname} [, {def}])
 				any	variable {varname} in buffer {expr}
+getchangelist({expr})		List	list of change list items
 getchar([expr])			Number	get one character from the user
 getcharmod()			Number	modifiers for the last typed character
 getcharsearch()			Dict	last character search
@@ -4278,6 +4279,22 @@ getbufvar({expr}, {varname} [, {def}])				*getbufvar()*
 			:let bufmodified = getbufvar(1, "&mod")
 			:echo "todo myvar = " . getbufvar("todo", "myvar")
 <
+getchangelist({expr})					*getchangelist()*
+		Returns the |changelist| for the buffer {expr}. For the use
+		of {expr}, see |bufname()| above. If buffer {expr} doesn't
+		exist, an empty list is returned.
+
+		The returned list contains two entries: a list with the change
+		locations and the current position in the list.  Each
+		entry in the change list is a dictionary with the following
+		entries:
+			col		column number
+			coladd		column offset for 'virtualedit'
+			lnum		line number
+		If buffer {expr} is the current buffer, then the current
+		position refers to the position in the list. For other
+		buffers, it is set to the length of the list.
+
 getchar([expr])						*getchar()*
 		Get a single character from the user or input stream.
 		If [expr] is omitted, wait until a character is available.

runtime/doc/usr_41.txt

@@ -807,6 +807,7 @@ Buffers, windows and the argument list:
 	getbufinfo()		get a list with buffer information
 	gettabinfo()		get a list with tab page information
 	getwininfo()		get a list with window information
+	getchangelist()		get a list of change list entries
 	getjumplist()		get a list of jump list entries
 
 Command line:					*command-line-functions*

src/Makefile

@@ -2127,6 +2127,7 @@ test_arglist \
 	test_cd \
 	test_cdo \
 	test_changedtick \
+	test_changelist \
 	test_channel \
 	test_charsearch \
 	test_charsearch_utf8 \

src/evalfunc.c

@@ -165,6 +165,7 @@ static void f_get(typval_T *argvars, typval_T *rettv);
 static void f_getbufinfo(typval_T *argvars, typval_T *rettv);
 static void f_getbufline(typval_T *argvars, typval_T *rettv);
 static void f_getbufvar(typval_T *argvars, typval_T *rettv);
+static void f_getchangelist(typval_T *argvars, typval_T *rettv);
 static void f_getchar(typval_T *argvars, typval_T *rettv);
 static void f_getcharmod(typval_T *argvars, typval_T *rettv);
 static void f_getcharsearch(typval_T *argvars, typval_T *rettv);
@@ -607,6 +608,7 @@ static struct fst
     {"getbufinfo",	0, 1, f_getbufinfo},
     {"getbufline",	2, 3, f_getbufline},
     {"getbufvar",	2, 3, f_getbufvar},
+    {"getchangelist",	1, 1, f_getchangelist},
     {"getchar",		0, 1, f_getchar},
     {"getcharmod",	0, 0, f_getcharmod},
     {"getcharsearch",	0, 0, f_getcharsearch},
@@ -4346,6 +4348,58 @@ f_getbufvar(typval_T *argvars, typval_T *rettv)
     --emsg_off;
 }
 
+/*
+ * "getchangelist()" function
+ */
+    static void
+f_getchangelist(typval_T *argvars, typval_T *rettv)
+{
+#ifdef FEAT_JUMPLIST
+    buf_T	*buf;
+    int		i;
+    list_T	*l;
+    dict_T	*d;
+#endif
+
+    if (rettv_list_alloc(rettv) != OK)
+	return;
+
+#ifdef FEAT_JUMPLIST
+    buf = find_buffer(&argvars[0]);
+    if (buf == NULL)
+	return;
+
+    l = list_alloc();
+    if (l == NULL)
+	return;
+
+    if (list_append_list(rettv->vval.v_list, l) == FAIL)
+	return;
+    /*
+     * The current window change list index tracks only the position in the
+     * current buffer change list. For other buffers, use the change list
+     * length as the current index.
+     */
+    list_append_number(rettv->vval.v_list,
+	    (varnumber_T)((buf == curwin->w_buffer)
+		? curwin->w_changelistidx : buf->b_changelistlen));
+
+    for (i = 0; i < buf->b_changelistlen; ++i)
+    {
+	if (buf->b_changelist[i].lnum == 0)
+	    continue;
+	if ((d = dict_alloc()) == NULL)
+	    return;
+	if (list_append_dict(l, d) == FAIL)
+	    return;
+	dict_add_nr_str(d, "lnum", (long)buf->b_changelist[i].lnum, NULL);
+	dict_add_nr_str(d, "col", (long)buf->b_changelist[i].col, NULL);
+# ifdef FEAT_VIRTUALEDIT
+	dict_add_nr_str(d, "coladd", (long)buf->b_changelist[i].coladd, NULL);
+# endif
+    }
+#endif
+}
 /*
  * "getchar()" function
  */

src/testdir/Make_all.mak

@@ -75,6 +75,7 @@ NEW_TESTS = test_arabic.res \
 	    test_breakindent.res \
 	    test_bufwintabinfo.res \
 	    test_cdo.res \
+	    test_changelist.res \
 	    test_channel.res \
 	    test_charsearch.res \
 	    test_cindent.res \

src/testdir/test_changelist.vim

@@ -0,0 +1,48 @@
+" Tests for the changelist functionality
+
+" Tests for the getchangelist() function
+func Test_getchangelist()
+  if !has("jumplist")
+    return
+  endif
+
+  bwipe!
+  enew
+  call assert_equal([], getchangelist(10))
+  call assert_equal([[], 0], getchangelist(bufnr('%')))
+
+  call writefile(['line1', 'line2', 'line3'], 'Xfile1.txt')
+  call writefile(['line1', 'line2', 'line3'], 'Xfile2.txt')
+
+  edit Xfile1.txt
+  exe "normal 1Goline\<C-G>u1.1"
+  exe "normal 3Goline\<C-G>u2.1"
+  exe "normal 5Goline\<C-G>u3.1"
+  normal g;
+  call assert_equal([[
+	      \ {'lnum' : 2, 'col' : 4, 'coladd' : 0},
+	      \ {'lnum' : 4, 'col' : 4, 'coladd' : 0},
+	      \ {'lnum' : 6, 'col' : 4, 'coladd' : 0}], 2],
+	      \ getchangelist(bufnr('%')))
+
+  hide edit Xfile2.txt
+  exe "normal 1GOline\<C-G>u1.0"
+  exe "normal 2Goline\<C-G>u2.0"
+  call assert_equal([[
+	      \ {'lnum' : 1, 'col' : 6, 'coladd' : 0},
+	      \ {'lnum' : 3, 'col' : 6, 'coladd' : 0}], 2],
+	      \ getchangelist(bufnr('%')))
+  hide enew
+
+  call assert_equal([[
+	      \ {'lnum' : 2, 'col' : 4, 'coladd' : 0},
+	      \ {'lnum' : 4, 'col' : 4, 'coladd' : 0},
+	      \ {'lnum' : 6, 'col' : 4, 'coladd' : 0}], 3], getchangelist(2))
+  call assert_equal([[
+	      \ {'lnum' : 1, 'col' : 6, 'coladd' : 0},
+	      \ {'lnum' : 3, 'col' : 6, 'coladd' : 0}], 2], getchangelist(3))
+
+  bwipe!
+  call delete('Xfile1.txt')
+  call delete('Xfile2.txt')
+endfunc

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1514,
 /**/
     1513,
 /**/