git-commit-vandalism/graph.c
Adam Simpkins 0724cb86c5 graph API: eliminate unnecessary indentation
This change improves the calculation of the amount of horizontal
padding, so that there is always exactly 1 space of padding.
Previously, most commits had 3 spaces of padding, but commits that
didn't have any children in the graph had only 1 space of padding.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-05-05 18:55:39 -07:00

946 lines
22 KiB
C

#include "cache.h"
#include "commit.h"
#include "graph.h"
#include "diff.h"
#include "revision.h"
/*
* TODO:
* - Add colors to the graph.
* Pick a color for each column, and print all characters
* in that column with the specified color.
*
* - Limit the number of columns, similar to the way gitk does.
* If we reach more than a specified number of columns, omit
* sections of some columns.
*
* - The output during the GRAPH_PRE_COMMIT and GRAPH_COLLAPSING states
* could be made more compact by printing horizontal lines, instead of
* long diagonal lines. For example, during collapsing, something like
* this: instead of this:
* | | | | | | | | | |
* | |_|_|/ | | | |/
* |/| | | | | |/|
* | | | | | |/| |
* |/| | |
* | | | |
*
* If there are several parallel diagonal lines, they will need to be
* replaced with horizontal lines on subsequent rows.
*/
struct column {
/*
* The parent commit of this column.
*/
struct commit *commit;
/*
* XXX: Once we add support for colors, struct column could also
* contain the color of its branch line.
*/
};
enum graph_state {
GRAPH_PADDING,
GRAPH_SKIP,
GRAPH_PRE_COMMIT,
GRAPH_COMMIT,
GRAPH_POST_MERGE,
GRAPH_COLLAPSING
};
struct git_graph {
/*
* The commit currently being processed
*/
struct commit *commit;
/*
* The number of parents this commit has.
* (Stored so we don't have to walk over them each time we need
* this number)
*/
int num_parents;
/*
* The width of the graph output for this commit.
* All rows for this commit are padded to this width, so that
* messages printed after the graph output are aligned.
*/
int width;
/*
* The next expansion row to print
* when state is GRAPH_PRE_COMMIT
*/
int expansion_row;
/*
* The current output state.
* This tells us what kind of line graph_next_line() should output.
*/
enum graph_state state;
/*
* The maximum number of columns that can be stored in the columns
* and new_columns arrays. This is also half the number of entries
* that can be stored in the mapping and new_mapping arrays.
*/
int column_capacity;
/*
* The number of columns (also called "branch lines" in some places)
*/
int num_columns;
/*
* The number of columns in the new_columns array
*/
int num_new_columns;
/*
* The number of entries in the mapping array
*/
int mapping_size;
/*
* The column state before we output the current commit.
*/
struct column *columns;
/*
* The new column state after we output the current commit.
* Only valid when state is GRAPH_COLLAPSING.
*/
struct column *new_columns;
/*
* An array that tracks the current state of each
* character in the output line during state GRAPH_COLLAPSING.
* Each entry is -1 if this character is empty, or a non-negative
* integer if the character contains a branch line. The value of
* the integer indicates the target position for this branch line.
* (I.e., this array maps the current column positions to their
* desired positions.)
*
* The maximum capacity of this array is always
* sizeof(int) * 2 * column_capacity.
*/
int *mapping;
/*
* A temporary array for computing the next mapping state
* while we are outputting a mapping line. This is stored as part
* of the git_graph simply so we don't have to allocate a new
* temporary array each time we have to output a collapsing line.
*/
int *new_mapping;
};
struct git_graph *graph_init(void)
{
struct git_graph *graph = xmalloc(sizeof(struct git_graph));
graph->commit = NULL;
graph->num_parents = 0;
graph->expansion_row = 0;
graph->state = GRAPH_PADDING;
graph->num_columns = 0;
graph->num_new_columns = 0;
graph->mapping_size = 0;
/*
* Allocate a reasonably large default number of columns
* We'll automatically grow columns later if we need more room.
*/
graph->column_capacity = 30;
graph->columns = xmalloc(sizeof(struct column) *
graph->column_capacity);
graph->new_columns = xmalloc(sizeof(struct column) *
graph->column_capacity);
graph->mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
graph->new_mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
return graph;
}
void graph_release(struct git_graph *graph)
{
free(graph->columns);
free(graph->new_columns);
free(graph->mapping);
free(graph);
}
static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
{
if (graph->column_capacity >= num_columns)
return;
do {
graph->column_capacity *= 2;
} while (graph->column_capacity < num_columns);
graph->columns = xrealloc(graph->columns,
sizeof(struct column) *
graph->column_capacity);
graph->new_columns = xrealloc(graph->new_columns,
sizeof(struct column) *
graph->column_capacity);
graph->mapping = xrealloc(graph->mapping,
sizeof(int) * 2 * graph->column_capacity);
graph->new_mapping = xrealloc(graph->new_mapping,
sizeof(int) * 2 * graph->column_capacity);
}
static void graph_insert_into_new_columns(struct git_graph *graph,
struct commit *commit,
int *mapping_index)
{
int i;
/*
* Ignore uinteresting and pruned commits
*/
if (commit->object.flags & (UNINTERESTING | TREESAME))
return;
/*
* If the commit is already in the new_columns list, we don't need to
* add it. Just update the mapping correctly.
*/
for (i = 0; i < graph->num_new_columns; i++) {
if (graph->new_columns[i].commit == commit) {
graph->mapping[*mapping_index] = i;
*mapping_index += 2;
return;
}
}
/*
* This commit isn't already in new_columns. Add it.
*/
graph->new_columns[graph->num_new_columns].commit = commit;
graph->mapping[*mapping_index] = graph->num_new_columns;
*mapping_index += 2;
graph->num_new_columns++;
}
static void graph_update_width(struct git_graph *graph,
int is_commit_in_existing_columns)
{
/*
* Compute the width needed to display the graph for this commit.
* This is the maximum width needed for any row. All other rows
* will be padded to this width.
*
* Compute the number of columns in the widest row:
* Count each existing column (graph->num_columns), and each new
* column added by this commit.
*/
int max_cols = graph->num_columns + graph->num_parents;
/*
* Even if the current commit has no parents, it still takes up a
* column for itself.
*/
if (graph->num_parents < 1)
max_cols++;
/*
* We added a column for the the current commit as part of
* graph->num_parents. If the current commit was already in
* graph->columns, then we have double counted it.
*/
if (is_commit_in_existing_columns)
max_cols--;
/*
* Each column takes up 2 spaces
*/
graph->width = max_cols * 2;
}
static void graph_update_columns(struct git_graph *graph)
{
struct commit_list *parent;
struct column *tmp_columns;
int max_new_columns;
int mapping_idx;
int i, seen_this, is_commit_in_columns;
/*
* Swap graph->columns with graph->new_columns
* graph->columns contains the state for the previous commit,
* and new_columns now contains the state for our commit.
*
* We'll re-use the old columns array as storage to compute the new
* columns list for the commit after this one.
*/
tmp_columns = graph->columns;
graph->columns = graph->new_columns;
graph->num_columns = graph->num_new_columns;
graph->new_columns = tmp_columns;
graph->num_new_columns = 0;
/*
* Now update new_columns and mapping with the information for the
* commit after this one.
*
* First, make sure we have enough room. At most, there will
* be graph->num_columns + graph->num_parents columns for the next
* commit.
*/
max_new_columns = graph->num_columns + graph->num_parents;
graph_ensure_capacity(graph, max_new_columns);
/*
* Clear out graph->mapping
*/
graph->mapping_size = 2 * max_new_columns;
for (i = 0; i < graph->mapping_size; i++)
graph->mapping[i] = -1;
/*
* Populate graph->new_columns and graph->mapping
*
* Some of the parents of this commit may already be in
* graph->columns. If so, graph->new_columns should only contain a
* single entry for each such commit. graph->mapping should
* contain information about where each current branch line is
* supposed to end up after the collapsing is performed.
*/
seen_this = 0;
mapping_idx = 0;
is_commit_in_columns = 1;
for (i = 0; i <= graph->num_columns; i++) {
struct commit *col_commit;
if (i == graph->num_columns) {
if (seen_this)
break;
is_commit_in_columns = 0;
col_commit = graph->commit;
} else {
col_commit = graph->columns[i].commit;
}
if (col_commit == graph->commit) {
seen_this = 1;
for (parent = graph->commit->parents;
parent;
parent = parent->next) {
graph_insert_into_new_columns(graph,
parent->item,
&mapping_idx);
}
} else {
graph_insert_into_new_columns(graph, col_commit,
&mapping_idx);
}
}
/*
* Shrink mapping_size to be the minimum necessary
*/
while (graph->mapping_size > 1 &&
graph->mapping[graph->mapping_size - 1] < 0)
graph->mapping_size--;
/*
* Compute graph->width for this commit
*/
graph_update_width(graph, is_commit_in_columns);
}
void graph_update(struct git_graph *graph, struct commit *commit)
{
struct commit_list *parent;
/*
* Set the new commit
*/
graph->commit = commit;
/*
* Count how many parents this commit has
*/
graph->num_parents = 0;
for (parent = commit->parents; parent; parent = parent->next)
graph->num_parents++;
/*
* Call graph_update_columns() to update
* columns, new_columns, and mapping.
*/
graph_update_columns(graph);
graph->expansion_row = 0;
/*
* Update graph->state.
*
* If the previous commit didn't get to the GRAPH_PADDING state,
* it never finished its output. Goto GRAPH_SKIP, to print out
* a line to indicate that portion of the graph is missing.
*
* Otherwise, if there are 3 or more parents, we need to print
* extra rows before the commit, to expand the branch lines around
* it and make room for it.
*
* If there are less than 3 parents, we can immediately print the
* commit line.
*/
if (graph->state != GRAPH_PADDING)
graph->state = GRAPH_SKIP;
else if (graph->num_parents >= 3)
graph->state = GRAPH_PRE_COMMIT;
else
graph->state = GRAPH_COMMIT;
}
static int graph_is_mapping_correct(struct git_graph *graph)
{
int i;
/*
* The mapping is up to date if each entry is at its target,
* or is 1 greater than its target.
* (If it is 1 greater than the target, '/' will be printed, so it
* will look correct on the next row.)
*/
for (i = 0; i < graph->mapping_size; i++) {
int target = graph->mapping[i];
if (target < 0)
continue;
if (target == (i / 2))
continue;
return 0;
}
return 1;
}
static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
{
/*
* Add additional spaces to the end of the strbuf, so that all
* lines for a particular commit have the same width.
*
* This way, fields printed to the right of the graph will remain
* aligned for the entire commit.
*/
int extra;
if (sb->len >= graph->width)
return;
extra = graph->width - sb->len;
strbuf_addf(sb, "%*s", (int) extra, "");
}
static void graph_output_padding_line(struct git_graph *graph,
struct strbuf *sb)
{
int i;
/*
* We could conceivable be called with a NULL commit
* if our caller has a bug, and invokes graph_next_line()
* immediately after graph_init(), without first calling
* graph_update(). Return without outputting anything in this
* case.
*/
if (!graph->commit)
return;
/*
* Output a padding row, that leaves all branch lines unchanged
*/
for (i = 0; i < graph->num_new_columns; i++) {
strbuf_addstr(sb, "| ");
}
graph_pad_horizontally(graph, sb);
}
static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
{
/*
* Output an ellipsis to indicate that a portion
* of the graph is missing.
*/
strbuf_addstr(sb, "...");
graph_pad_horizontally(graph, sb);
if (graph->num_parents >= 3)
graph->state = GRAPH_PRE_COMMIT;
else
graph->state = GRAPH_COMMIT;
}
static void graph_output_pre_commit_line(struct git_graph *graph,
struct strbuf *sb)
{
int num_expansion_rows;
int i, seen_this;
/*
* This function formats a row that increases the space around a commit
* with multiple parents, to make room for it. It should only be
* called when there are 3 or more parents.
*
* We need 2 extra rows for every parent over 2.
*/
assert(graph->num_parents >= 3);
num_expansion_rows = (graph->num_parents - 2) * 2;
/*
* graph->expansion_row tracks the current expansion row we are on.
* It should be in the range [0, num_expansion_rows - 1]
*/
assert(0 <= graph->expansion_row &&
graph->expansion_row < num_expansion_rows);
/*
* Output the row
*/
seen_this = 0;
for (i = 0; i < graph->num_columns; i++) {
struct column *col = &graph->columns[i];
if (col->commit == graph->commit) {
seen_this = 1;
strbuf_addf(sb, "| %*s", graph->expansion_row, "");
} else if (seen_this) {
strbuf_addstr(sb, "\\ ");
} else {
strbuf_addstr(sb, "| ");
}
}
graph_pad_horizontally(graph, sb);
/*
* Increment graph->expansion_row,
* and move to state GRAPH_COMMIT if necessary
*/
graph->expansion_row++;
if (graph->expansion_row >= num_expansion_rows)
graph->state = GRAPH_COMMIT;
}
void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
{
int seen_this = 0;
int i, j;
/*
* Output the row containing this commit
* Iterate up to and including graph->num_columns,
* since the current commit may not be in any of the existing
* columns. (This happens when the current commit doesn't have any
* children that we have already processed.)
*/
seen_this = 0;
for (i = 0; i <= graph->num_columns; i++) {
struct commit *col_commit;
if (i == graph->num_columns) {
if (seen_this)
break;
col_commit = graph->commit;
} else {
col_commit = graph->columns[i].commit;
}
if (col_commit == graph->commit) {
seen_this = 1;
if (graph->num_parents > 1)
strbuf_addch(sb, 'M');
else
strbuf_addch(sb, '*');
if (graph->num_parents < 2)
strbuf_addch(sb, ' ');
else if (graph->num_parents == 2)
strbuf_addstr(sb, " ");
else {
int num_dashes =
((graph->num_parents - 2) * 2) - 1;
for (j = 0; j < num_dashes; j++)
strbuf_addch(sb, '-');
strbuf_addstr(sb, ". ");
}
} else if (seen_this && (graph->num_parents > 1)) {
strbuf_addstr(sb, "\\ ");
} else {
strbuf_addstr(sb, "| ");
}
}
graph_pad_horizontally(graph, sb);
/*
* Update graph->state
*/
if (graph->num_parents > 1)
graph->state = GRAPH_POST_MERGE;
else if (graph_is_mapping_correct(graph))
graph->state = GRAPH_PADDING;
else
graph->state = GRAPH_COLLAPSING;
}
void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
{
int seen_this = 0;
int i, j;
/*
* Output the post-merge row
*/
for (i = 0; i <= graph->num_columns; i++) {
struct commit *col_commit;
if (i == graph->num_columns) {
if (seen_this)
break;
col_commit = graph->commit;
} else {
col_commit = graph->columns[i].commit;
}
if (col_commit == graph->commit) {
seen_this = 1;
strbuf_addch(sb, '|');
for (j = 0; j < graph->num_parents - 1; j++)
strbuf_addstr(sb, "\\ ");
if (graph->num_parents == 2)
strbuf_addch(sb, ' ');
} else if (seen_this && (graph->num_parents > 2)) {
strbuf_addstr(sb, "\\ ");
} else {
strbuf_addstr(sb, "| ");
}
}
graph_pad_horizontally(graph, sb);
/*
* Update graph->state
*/
if (graph_is_mapping_correct(graph))
graph->state = GRAPH_PADDING;
else
graph->state = GRAPH_COLLAPSING;
}
void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
{
int i;
int *tmp_mapping;
/*
* Clear out the new_mapping array
*/
for (i = 0; i < graph->mapping_size; i++)
graph->new_mapping[i] = -1;
for (i = 0; i < graph->mapping_size; i++) {
int target = graph->mapping[i];
if (target < 0)
continue;
/*
* Since update_columns() always inserts the leftmost
* column first, each branch's target location should
* always be either its current location or to the left of
* its current location.
*
* We never have to move branches to the right. This makes
* the graph much more legible, since whenever branches
* cross, only one is moving directions.
*/
assert(target * 2 <= i);
if (target * 2 == i) {
/*
* This column is already in the
* correct place
*/
assert(graph->new_mapping[i] == -1);
graph->new_mapping[i] = target;
} else if (graph->new_mapping[i - 1] < 0) {
/*
* Nothing is to the left.
* Move to the left by one
*/
graph->new_mapping[i - 1] = target;
} else if (graph->new_mapping[i - 1] == target) {
/*
* There is a branch line to our left
* already, and it is our target. We
* combine with this line, since we share
* the same parent commit.
*
* We don't have to add anything to the
* output or new_mapping, since the
* existing branch line has already taken
* care of it.
*/
} else {
/*
* There is a branch line to our left,
* but it isn't our target. We need to
* cross over it.
*
* The space just to the left of this
* branch should always be empty.
*/
assert(graph->new_mapping[i - 1] > target);
assert(graph->new_mapping[i - 2] < 0);
graph->new_mapping[i - 2] = target;
}
}
/*
* The new mapping may be 1 smaller than the old mapping
*/
if (graph->new_mapping[graph->mapping_size - 1] < 0)
graph->mapping_size--;
/*
* Output out a line based on the new mapping info
*/
for (i = 0; i < graph->mapping_size; i++) {
int target = graph->new_mapping[i];
if (target < 0)
strbuf_addch(sb, ' ');
else if (target * 2 == i)
strbuf_addch(sb, '|');
else
strbuf_addch(sb, '/');
}
graph_pad_horizontally(graph, sb);
/*
* Swap mapping and new_mapping
*/
tmp_mapping = graph->mapping;
graph->mapping = graph->new_mapping;
graph->new_mapping = tmp_mapping;
/*
* If graph->mapping indicates that all of the branch lines
* are already in the correct positions, we are done.
* Otherwise, we need to collapse some branch lines together.
*/
if (graph_is_mapping_correct(graph))
graph->state = GRAPH_PADDING;
}
int graph_next_line(struct git_graph *graph, struct strbuf *sb)
{
switch (graph->state) {
case GRAPH_PADDING:
graph_output_padding_line(graph, sb);
return 0;
case GRAPH_SKIP:
graph_output_skip_line(graph, sb);
return 0;
case GRAPH_PRE_COMMIT:
graph_output_pre_commit_line(graph, sb);
return 0;
case GRAPH_COMMIT:
graph_output_commit_line(graph, sb);
return 1;
case GRAPH_POST_MERGE:
graph_output_post_merge_line(graph, sb);
return 0;
case GRAPH_COLLAPSING:
graph_output_collapsing_line(graph, sb);
return 0;
}
assert(0);
return 0;
}
void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
{
int i, j;
if (graph->state != GRAPH_COMMIT) {
graph_next_line(graph, sb);
return;
}
/*
* Output the row containing this commit
* Iterate up to and including graph->num_columns,
* since the current commit may not be in any of the existing
* columns. (This happens when the current commit doesn't have any
* children that we have already processed.)
*/
for (i = 0; i < graph->num_columns; i++) {
struct commit *col_commit = graph->columns[i].commit;
if (col_commit == graph->commit) {
strbuf_addch(sb, '|');
if (graph->num_parents < 3)
strbuf_addch(sb, ' ');
else {
int num_spaces = ((graph->num_parents - 2) * 2);
for (j = 0; j < num_spaces; j++)
strbuf_addch(sb, ' ');
}
} else {
strbuf_addstr(sb, "| ");
}
}
graph_pad_horizontally(graph, sb);
}
int graph_is_commit_finished(struct git_graph const *graph)
{
return (graph->state == GRAPH_PADDING);
}
void graph_show_commit(struct git_graph *graph)
{
struct strbuf msgbuf;
int shown_commit_line = 0;
if (!graph)
return;
strbuf_init(&msgbuf, 0);
while (!shown_commit_line) {
shown_commit_line = graph_next_line(graph, &msgbuf);
fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
if (!shown_commit_line)
putchar('\n');
strbuf_setlen(&msgbuf, 0);
}
strbuf_release(&msgbuf);
}
void graph_show_oneline(struct git_graph *graph)
{
struct strbuf msgbuf;
if (!graph)
return;
strbuf_init(&msgbuf, 0);
graph_next_line(graph, &msgbuf);
fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
strbuf_release(&msgbuf);
}
void graph_show_padding(struct git_graph *graph)
{
struct strbuf msgbuf;
if (!graph)
return;
strbuf_init(&msgbuf, 0);
graph_padding_line(graph, &msgbuf);
fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
strbuf_release(&msgbuf);
}
int graph_show_remainder(struct git_graph *graph)
{
struct strbuf msgbuf;
int shown = 0;
if (!graph)
return 0;
if (graph_is_commit_finished(graph))
return 0;
strbuf_init(&msgbuf, 0);
for (;;) {
graph_next_line(graph, &msgbuf);
fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
strbuf_setlen(&msgbuf, 0);
shown = 1;
if (!graph_is_commit_finished(graph))
putchar('\n');
else
break;
}
strbuf_release(&msgbuf);
return shown;
}
void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
{
char *p;
if (!graph) {
fwrite(sb->buf, sizeof(char), sb->len, stdout);
return;
}
/*
* Print the strbuf line by line,
* and display the graph info before each line but the first.
*/
p = sb->buf;
while (p) {
size_t len;
char *next_p = strchr(p, '\n');
if (next_p) {
next_p++;
len = next_p - p;
} else {
len = (sb->buf + sb->len) - p;
}
fwrite(p, sizeof(char), len, stdout);
if (next_p && *next_p != '\0')
graph_show_oneline(graph);
p = next_p;
}
}
void graph_show_commit_msg(struct git_graph *graph,
struct strbuf const *sb)
{
int newline_terminated;
if (!graph) {
/*
* If there's no graph, just print the message buffer.
*
* The message buffer for CMIT_FMT_ONELINE and
* CMIT_FMT_USERFORMAT are already missing a terminating
* newline. All of the other formats should have it.
*/
fwrite(sb->buf, sizeof(char), sb->len, stdout);
return;
}
newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
/*
* Show the commit message
*/
graph_show_strbuf(graph, sb);
/*
* If there is more output needed for this commit, show it now
*/
if (!graph_is_commit_finished(graph)) {
/*
* If sb doesn't have a terminating newline, print one now,
* so we can start the remainder of the graph output on a
* new line.
*/
if (!newline_terminated)
putchar('\n');
graph_show_remainder(graph);
/*
* If sb ends with a newline, our output should too.
*/
if (newline_terminated)
putchar('\n');
}
}