graph: automatically track display width of graph lines
All the output functions called by `graph_next_line()` currently keep track of how many printable chars they've written to the buffer, before calling `graph_pad_horizontally()` to pad the line with spaces. Some functions do this by incrementing a counter whenever they write to the buffer, and others do it by encoding an assumption about how many chars are written, as in: graph_pad_horizontally(graph, sb, graph->num_columns * 2); This adds a fair amount of noise to the functions' logic and is easily broken if one forgets to increment the right counter or update the calculations used for padding. To make this easier to use, I'm introducing a new struct called `graph_line` that wraps a `strbuf` and keeps count of its display width implicitly. `graph_next_line()` wraps this around the `struct strbuf *` it's given and passes a `struct graph_line *` to the output functions, which use its interface. The `graph_line` interface wraps the `strbuf_addch()`, `strbuf_addchars()` and `strbuf_addstr()` functions, and adds the `graph_line_write_column()` function for adding a single character with color formatting. The `graph_pad_horizontally()` function can then use the `width` field from the struct rather than taking a character count as a parameter. Signed-off-by: James Coglan <jcoglan@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
James Coglan committed
Oct 15, 2019 at 23:47 UTC
fbccf255f9449c2f617d875ebf78b9f1730fae5d
1 file changed
+99
-95
graph.c
+99
-95
@@ -112,14 +112,42 @@ static const char *column_get_color_code(unsigned short color)
112
return column_colors[color];
113
}
114
115
-static void strbuf_write_column(struct strbuf *sb, const struct column *c,
116
- char col_char)
115
+struct graph_line {
116
+ struct strbuf *buf;
117
+ size_t width;
118
+};
119
+
120
+static inline void graph_line_addch(struct graph_line *line, int c)
121
+{
122
+ strbuf_addch(line->buf, c);
123
+ line->width++;
124
+}
125
+
126
+static inline void graph_line_addchars(struct graph_line *line, int c, size_t n)
127
+{
128
+ strbuf_addchars(line->buf, c, n);
129
+ line->width += n;
130
+}
131
+
132
+static inline void graph_line_addstr(struct graph_line *line, const char *s)
133
+{
134
+ strbuf_addstr(line->buf, s);
135
+ line->width += strlen(s);
136
+}
137
+
138
+static inline void graph_line_addcolor(struct graph_line *line, unsigned short color)
139
+{
140
+ strbuf_addstr(line->buf, column_get_color_code(color));
141
+}
142
+
143
+static void graph_line_write_column(struct graph_line *line, const struct column *c,
144
+ char col_char)
145
{
146
if (c->color < column_colors_max)
119
- strbuf_addstr(sb, column_get_color_code(c->color));
120
- strbuf_addch(sb, col_char);
147
+ graph_line_addcolor(line, c->color);
148
+ graph_line_addch(line, col_char);
149
if (c->color < column_colors_max)
122
- strbuf_addstr(sb, column_get_color_code(column_colors_max));
150
+ graph_line_addcolor(line, column_colors_max);
151
}
152
153
struct git_graph {
@@ -686,8 +714,7 @@ static int graph_is_mapping_correct(struct git_graph *graph)
714
return 1;
715
}
716
689
-static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
690
- int chars_written)
717
+static void graph_pad_horizontally(struct git_graph *graph, struct graph_line *line)
718
{
719
/*
720
* Add additional spaces to the end of the strbuf, so that all
@@ -696,12 +723,12 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
723
* This way, fields printed to the right of the graph will remain
724
* aligned for the entire commit.
725
*/
699
- if (chars_written < graph->width)
700
- strbuf_addchars(sb, ' ', graph->width - chars_written);
726
+ if (line->width < graph->width)
727
+ graph_line_addchars(line, ' ', graph->width - line->width);
728
}
729
730
static void graph_output_padding_line(struct git_graph *graph,
704
- struct strbuf *sb)
731
+ struct graph_line *line)
732
{
733
int i;
734
@@ -719,11 +746,11 @@ static void graph_output_padding_line(struct git_graph *graph,
746
* Output a padding row, that leaves all branch lines unchanged
747
*/
748
for (i = 0; i < graph->num_new_columns; i++) {
722
- strbuf_write_column(sb, &graph->new_columns[i], '|');
723
- strbuf_addch(sb, ' ');
749
+ graph_line_write_column(line, &graph->new_columns[i], '|');
750
+ graph_line_addch(line, ' ');
751
}
752
726
- graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
753
+ graph_pad_horizontally(graph, line);
754
}
755
756
@@ -733,14 +760,14 @@ int graph_width(struct git_graph *graph)
760
}
761
762
736
-static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
763
+static void graph_output_skip_line(struct git_graph *graph, struct graph_line *line)
764
{
765
/*
766
* Output an ellipsis to indicate that a portion
767
* of the graph is missing.
768
*/
742
- strbuf_addstr(sb, "...");
743
- graph_pad_horizontally(graph, sb, 3);
769
+ graph_line_addstr(line, "...");
770
+ graph_pad_horizontally(graph, line);
771
772
if (graph->num_parents >= 3 &&
773
graph->commit_index < (graph->num_columns - 1))
@@ -750,11 +777,10 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
777
}
778
779
static void graph_output_pre_commit_line(struct git_graph *graph,
753
- struct strbuf *sb)
780
+ struct graph_line *line)
781
{
782
int num_expansion_rows;
783
int i, seen_this;
757
- int chars_written;
784
785
/*
786
* This function formats a row that increases the space around a commit
@@ -777,14 +803,12 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
803
* Output the row
804
*/
805
seen_this = 0;
780
- chars_written = 0;
806
for (i = 0; i < graph->num_columns; i++) {
807
struct column *col = &graph->columns[i];
808
if (col->commit == graph->commit) {
809
seen_this = 1;
785
- strbuf_write_column(sb, col, '|');
786
- strbuf_addchars(sb, ' ', graph->expansion_row);
787
- chars_written += 1 + graph->expansion_row;
810
+ graph_line_write_column(line, col, '|');
811
+ graph_line_addchars(line, ' ', graph->expansion_row);
812
} else if (seen_this && (graph->expansion_row == 0)) {
813
/*
814
* This is the first line of the pre-commit output.
@@ -797,22 +821,18 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
821
*/
822
if (graph->prev_state == GRAPH_POST_MERGE &&
823
graph->prev_commit_index < i)
800
- strbuf_write_column(sb, col, '\\');
824
+ graph_line_write_column(line, col, '\\');
825
else
802
- strbuf_write_column(sb, col, '|');
803
- chars_written++;
826
+ graph_line_write_column(line, col, '|');
827
} else if (seen_this && (graph->expansion_row > 0)) {
805
- strbuf_write_column(sb, col, '\\');
806
- chars_written++;
828
+ graph_line_write_column(line, col, '\\');
829
} else {
808
- strbuf_write_column(sb, col, '|');
809
- chars_written++;
830
+ graph_line_write_column(line, col, '|');
831
}
811
- strbuf_addch(sb, ' ');
812
- chars_written++;
832
+ graph_line_addch(line, ' ');
833
}
834
815
- graph_pad_horizontally(graph, sb, chars_written);
835
+ graph_pad_horizontally(graph, line);
836
837
/*
838
* Increment graph->expansion_row,
@@ -823,7 +843,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
843
graph_update_state(graph, GRAPH_COMMIT);
844
}
845
826
-static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
846
+static void graph_output_commit_char(struct git_graph *graph, struct graph_line *line)
847
{
848
/*
849
* For boundary commits, print 'o'
@@ -831,22 +851,20 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
851
*/
852
if (graph->commit->object.flags & BOUNDARY) {
853
assert(graph->revs->boundary);
834
- strbuf_addch(sb, 'o');
854
+ graph_line_addch(line, 'o');
855
return;
856
}
857
858
/*
859
* get_revision_mark() handles all other cases without assert()
860
*/
841
- strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
861
+ graph_line_addstr(line, get_revision_mark(graph->revs, graph->commit));
862
}
863
864
/*
845
- * Draw the horizontal dashes of an octopus merge and return the number of
846
- * characters written.
865
+ * Draw the horizontal dashes of an octopus merge.
866
*/
848
-static int graph_draw_octopus_merge(struct git_graph *graph,
849
- struct strbuf *sb)
867
+static void graph_draw_octopus_merge(struct git_graph *graph, struct graph_line *line)
868
{
869
/*
870
* Here dashless_parents represents the number of parents which don't
@@ -886,17 +904,16 @@ static int graph_draw_octopus_merge(struct git_graph *graph,
904
905
int i;
906
for (i = 0; i < dashful_parents; i++) {
889
- strbuf_write_column(sb, &graph->new_columns[i+first_col], '-');
890
- strbuf_write_column(sb, &graph->new_columns[i+first_col],
891
- i == dashful_parents-1 ? '.' : '-');
907
+ graph_line_write_column(line, &graph->new_columns[i+first_col], '-');
908
+ graph_line_write_column(line, &graph->new_columns[i+first_col],
909
+ i == dashful_parents-1 ? '.' : '-');
910
}
893
- return 2 * dashful_parents;
911
}
912
896
-static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
913
+static void graph_output_commit_line(struct git_graph *graph, struct graph_line *line)
914
{
915
int seen_this = 0;
899
- int i, chars_written;
916
+ int i;
917
918
/*
919
* Output the row containing this commit
@@ -906,7 +923,6 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
923
* children that we have already processed.)
924
*/
925
seen_this = 0;
909
- chars_written = 0;
926
for (i = 0; i <= graph->num_columns; i++) {
927
struct column *col = &graph->columns[i];
928
struct commit *col_commit;
@@ -920,15 +936,12 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
936
937
if (col_commit == graph->commit) {
938
seen_this = 1;
923
- graph_output_commit_char(graph, sb);
924
- chars_written++;
939
+ graph_output_commit_char(graph, line);
940
941
if (graph->num_parents > 2)
927
- chars_written += graph_draw_octopus_merge(graph,
928
- sb);
942
+ graph_draw_octopus_merge(graph, line);
943
} else if (seen_this && (graph->num_parents > 2)) {
930
- strbuf_write_column(sb, col, '\\');
931
- chars_written++;
944
+ graph_line_write_column(line, col, '\\');
945
} else if (seen_this && (graph->num_parents == 2)) {
946
/*
947
* This is a 2-way merge commit.
@@ -945,19 +958,16 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
958
*/
959
if (graph->prev_state == GRAPH_POST_MERGE &&
960
graph->prev_commit_index < i)
948
- strbuf_write_column(sb, col, '\\');
961
+ graph_line_write_column(line, col, '\\');
962
else
950
- strbuf_write_column(sb, col, '|');
951
- chars_written++;
963
+ graph_line_write_column(line, col, '|');
964
} else {
953
- strbuf_write_column(sb, col, '|');
954
- chars_written++;
965
+ graph_line_write_column(line, col, '|');
966
}
956
- strbuf_addch(sb, ' ');
957
- chars_written++;
967
+ graph_line_addch(line, ' ');
968
}
969
960
- graph_pad_horizontally(graph, sb, chars_written);
970
+ graph_pad_horizontally(graph, line);
971
972
/*
973
* Update graph->state
@@ -981,15 +991,14 @@ static struct column *find_new_column_by_commit(struct git_graph *graph,
991
return NULL;
992
}
993
984
-static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
994
+static void graph_output_post_merge_line(struct git_graph *graph, struct graph_line *line)
995
{
996
int seen_this = 0;
987
- int i, j, chars_written;
997
+ int i, j;
998
999
/*
1000
* Output the post-merge row
1001
*/
992
- chars_written = 0;
1002
for (i = 0; i <= graph->num_columns; i++) {
1003
struct column *col = &graph->columns[i];
1004
struct commit *col_commit;
@@ -1016,29 +1025,25 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
1025
par_column = find_new_column_by_commit(graph, parents->item);
1026
assert(par_column);
1027
1019
- strbuf_write_column(sb, par_column, '|');
1020
- chars_written++;
1028
+ graph_line_write_column(line, par_column, '|');
1029
for (j = 0; j < graph->num_parents - 1; j++) {
1030
parents = next_interesting_parent(graph, parents);
1031
assert(parents);
1032
par_column = find_new_column_by_commit(graph, parents->item);
1033
assert(par_column);
1026
- strbuf_write_column(sb, par_column, '\\');
1027
- strbuf_addch(sb, ' ');
1034
+ graph_line_write_column(line, par_column, '\\');
1035
+ graph_line_addch(line, ' ');
1036
}
1029
- chars_written += j * 2;
1037
} else if (seen_this) {
1031
- strbuf_write_column(sb, col, '\\');
1032
- strbuf_addch(sb, ' ');
1033
- chars_written += 2;
1038
+ graph_line_write_column(line, col, '\\');
1039
+ graph_line_addch(line, ' ');
1040
} else {
1035
- strbuf_write_column(sb, col, '|');
1036
- strbuf_addch(sb, ' ');
1037
- chars_written += 2;
1041
+ graph_line_write_column(line, col, '|');
1042
+ graph_line_addch(line, ' ');
1043
}
1044
}
1045
1041
- graph_pad_horizontally(graph, sb, chars_written);
1046
+ graph_pad_horizontally(graph, line);
1047
1048
/*
1049
* Update graph->state
@@ -1049,7 +1054,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
1054
graph_update_state(graph, GRAPH_COLLAPSING);
1055
}
1056
1052
-static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
1057
+static void graph_output_collapsing_line(struct git_graph *graph, struct graph_line *line)
1058
{
1059
int i;
1060
short used_horizontal = 0;
@@ -1159,9 +1164,9 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
1164
for (i = 0; i < graph->mapping_size; i++) {
1165
int target = graph->new_mapping[i];
1166
if (target < 0)
1162
- strbuf_addch(sb, ' ');
1167
+ graph_line_addch(line, ' ');
1168
else if (target * 2 == i)
1164
- strbuf_write_column(sb, &graph->new_columns[target], '|');
1169
+ graph_line_write_column(line, &graph->new_columns[target], '|');
1170
else if (target == horizontal_edge_target &&
1171
i != horizontal_edge - 1) {
1172
/*
@@ -1172,16 +1177,16 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
1177
if (i != (target * 2)+3)
1178
graph->new_mapping[i] = -1;
1179
used_horizontal = 1;
1175
- strbuf_write_column(sb, &graph->new_columns[target], '_');
1180
+ graph_line_write_column(line, &graph->new_columns[target], '_');
1181
} else {
1182
if (used_horizontal && i < horizontal_edge)
1183
graph->new_mapping[i] = -1;
1179
- strbuf_write_column(sb, &graph->new_columns[target], '/');
1184
+ graph_line_write_column(line, &graph->new_columns[target], '/');
1185
1186
}
1187
}
1188
1184
- graph_pad_horizontally(graph, sb, graph->mapping_size);
1189
+ graph_pad_horizontally(graph, line);
1190
1191
/*
1192
* Swap mapping and new_mapping
@@ -1199,24 +1204,26 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
1204
1205
int graph_next_line(struct git_graph *graph, struct strbuf *sb)
1206
{
1207
+ struct graph_line line = { .buf = sb, .width = 0 };
1208
+
1209
switch (graph->state) {
1210
case GRAPH_PADDING:
1204
- graph_output_padding_line(graph, sb);
1211
+ graph_output_padding_line(graph, &line);
1212
return 0;
1213
case GRAPH_SKIP:
1207
- graph_output_skip_line(graph, sb);
1214
+ graph_output_skip_line(graph, &line);
1215
return 0;
1216
case GRAPH_PRE_COMMIT:
1210
- graph_output_pre_commit_line(graph, sb);
1217
+ graph_output_pre_commit_line(graph, &line);
1218
return 0;
1219
case GRAPH_COMMIT:
1213
- graph_output_commit_line(graph, sb);
1220
+ graph_output_commit_line(graph, &line);
1221
return 1;
1222
case GRAPH_POST_MERGE:
1216
- graph_output_post_merge_line(graph, sb);
1223
+ graph_output_post_merge_line(graph, &line);
1224
return 0;
1225
case GRAPH_COLLAPSING:
1219
- graph_output_collapsing_line(graph, sb);
1226
+ graph_output_collapsing_line(graph, &line);
1227
return 0;
1228
}
1229
@@ -1227,7 +1234,7 @@ int graph_next_line(struct git_graph *graph, struct strbuf *sb)
1234
static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
1235
{
1236
int i;
1230
- int chars_written = 0;
1237
+ struct graph_line line = { .buf = sb, .width = 0 };
1238
1239
if (graph->state != GRAPH_COMMIT) {
1240
graph_next_line(graph, sb);
@@ -1244,20 +1251,17 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
1251
for (i = 0; i < graph->num_columns; i++) {
1252
struct column *col = &graph->columns[i];
1253
1247
- strbuf_write_column(sb, col, '|');
1248
- chars_written++;
1254
+ graph_line_write_column(&line, col, '|');
1255
1256
if (col->commit == graph->commit && graph->num_parents > 2) {
1257
int len = (graph->num_parents - 2) * 2;
1252
- strbuf_addchars(sb, ' ', len);
1253
- chars_written += len;
1258
+ graph_line_addchars(&line, ' ', len);
1259
} else {
1255
- strbuf_addch(sb, ' ');
1256
- chars_written++;
1260
+ graph_line_addch(&line, ' ');
1261
}
1262
}
1263
1260
- graph_pad_horizontally(graph, sb, chars_written);
1264
+ graph_pad_horizontally(graph, &line);
1265
1266
/*
1267
* Update graph->prev_state since we have output a padding line