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In side-by-side diff, add support for marking individual characters.

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Refuses to do so if the left hand side of the diff has different amount of
differing lines to the right hand side to avoid confusion.

Note that I use the naive dynamic programming approach for calculating the
longest common subsequence. We could probably be more efficient by using a
better algorithm. The LCS calculating function is O(n*m) and uses up n*m
amount of memory too (so if we we compare two strings of length 100, I use
an array of 10000 for calculating the LCS). Might want to not calculate LCS
if the length of the line is too large.

Signed-off-by: Ragnar Ouchterlony <ragnar@lysator.liu.se>
This commit is contained in:
Ragnar Ouchterlony 2009-10-25 18:13:22 +01:00 committed by Lars Hjemli
parent 4a198e4b8e
commit 735e15e38a
2 changed files with 130 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
cgit.css
View File

@ -627,6 +627,11 @@ table.ssdiff td.add_dark {
min-width: 50%;
}
table.ssdiff span.add {
background: #cfc;
font-weight: bold;
}
table.ssdiff td.del {
color: black;
background: #fcc;
@ -639,6 +644,11 @@ table.ssdiff td.del_dark {
min-width: 50%;
}
table.ssdiff span.del {
background: #fcc;
font-weight: bold;
}
table.ssdiff td.changed {
color: black;
background: #ffc;

145
ui-ssdiff.c
View File

@ -15,6 +15,52 @@ struct deferred_lines {
static struct deferred_lines *deferred_old, *deferred_old_last;
static struct deferred_lines *deferred_new, *deferred_new_last;
static char *longest_common_subsequence(char *A, char *B)
{
int i, j, ri;
int m = strlen(A);
int n = strlen(B);
int L[m + 1][n + 1];
int tmp1, tmp2;
int lcs_length;
char *result;
for (i = m; i >= 0; i--) {
for (j = n; j >= 0; j--) {
if (A[i] == '\0' || B[j] == '\0') {
L[i][j] = 0;
} else if (A[i] == B[j]) {
L[i][j] = 1 + L[i + 1][j + 1];
} else {
tmp1 = L[i + 1][j];
tmp2 = L[i][j + 1];
L[i][j] = (tmp1 > tmp2 ? tmp1 : tmp2);
}
}
}
lcs_length = L[0][0];
result = xmalloc(lcs_length + 2);
memset(result, 0, sizeof(*result) * (lcs_length + 2));
ri = 0;
i = 0;
j = 0;
while (i < m && j < n) {
if (A[i] == B[j]) {
result[ri] = A[i];
ri += 1;
i += 1;
j += 1;
} else if (L[i + 1][j] >= L[i][j + 1]) {
i += 1;
} else {
j += 1;
}
}
return result;
}
static int line_from_hunk(char *line, char type)
{
char *buf1, *buf2;
@ -73,6 +119,17 @@ static char *replace_tabs(char *line)
return result;
}
static int calc_deferred_lines(struct deferred_lines *start)
{
struct deferred_lines *item = start;
int result = 0;
while (item) {
result += 1;
item = item->next;
}
return result;
}
static void deferred_old_add(char *line, int line_no)
{
struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
@ -101,9 +158,45 @@ static void deferred_new_add(char *line, int line_no)
}
}
static void print_ssdiff_line(char *class, int old_line_no, char *old_line,
int new_line_no, char *new_line)
static void print_part_with_lcs(char *class, char *line, char *lcs)
{
int line_len = strlen(line);
int i, j;
char c[2] = " ";
int same = 1;
j = 0;
for (i = 0; i < line_len; i++) {
c[0] = line[i];
if (same) {
if (line[i] == lcs[j])
j += 1;
else {
same = 0;
htmlf("<span class='%s'>", class);
}
} else if (line[i] == lcs[j]) {
same = 1;
htmlf("</span>");
j += 1;
}
html_txt(c);
}
}
static void print_ssdiff_line(char *class,
int old_line_no,
char *old_line,
int new_line_no,
char *new_line, int individual_chars)
{
char *lcs = NULL;
if (old_line)
old_line = replace_tabs(old_line + 1);
if (new_line)
new_line = replace_tabs(new_line + 1);
if (individual_chars && old_line && new_line)
lcs = longest_common_subsequence(old_line, new_line);
html("<tr>");
if (old_line_no > 0)
htmlf("<td class='lineno'>%d</td><td class='%s'>",
@ -112,15 +205,14 @@ static void print_ssdiff_line(char *class, int old_line_no, char *old_line,
htmlf("<td class='lineno'></td><td class='%s'>", class);
else
htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
if (old_line) {
old_line = replace_tabs(old_line + 1);
html_txt(old_line);
free(old_line);
if (lcs)
print_part_with_lcs("del", old_line, lcs);
else
html_txt(old_line);
}
html("</td>");
if (new_line_no > 0)
htmlf("<td class='lineno'>%d</td><td class='%s'>",
new_line_no, class);
@ -128,24 +220,29 @@ static void print_ssdiff_line(char *class, int old_line_no, char *old_line,
htmlf("<td class='lineno'></td><td class='%s'>", class);
else
htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
if (new_line) {
new_line = replace_tabs(new_line + 1);
html_txt(new_line);
free(new_line);
if (lcs)
print_part_with_lcs("add", new_line, lcs);
else
html_txt(new_line);
}
html("</td></tr>");
if (lcs)
free(lcs);
if (new_line)
free(new_line);
if (old_line)
free(old_line);
}
static void print_deferred_old_lines()
{
struct deferred_lines *iter_old, *tmp;
iter_old = deferred_old;
while (iter_old) {
print_ssdiff_line("del", iter_old->line_no,
iter_old->line, -1, NULL);
iter_old->line, -1, NULL, 0);
tmp = iter_old->next;
free(iter_old);
iter_old = tmp;
@ -155,11 +252,10 @@ static void print_deferred_old_lines()
static void print_deferred_new_lines()
{
struct deferred_lines *iter_new, *tmp;
iter_new = deferred_new;
while (iter_new) {
print_ssdiff_line("add", -1, NULL, iter_new->line_no,
iter_new->line);
print_ssdiff_line("add", -1, NULL,
iter_new->line_no, iter_new->line, 0);
tmp = iter_new->next;
free(iter_new);
iter_new = tmp;
@ -169,6 +265,9 @@ static void print_deferred_new_lines()
static void print_deferred_changed_lines()
{
struct deferred_lines *iter_old, *iter_new, *tmp;
int n_old_lines = calc_deferred_lines(deferred_old);
int n_new_lines = calc_deferred_lines(deferred_new);
int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
iter_old = deferred_old;
iter_new = deferred_new;
@ -176,14 +275,14 @@ static void print_deferred_changed_lines()
if (iter_old && iter_new)
print_ssdiff_line("changed", iter_old->line_no,
iter_old->line,
iter_new->line_no, iter_new->line);
iter_new->line_no, iter_new->line,
individual_chars);
else if (iter_old)
print_ssdiff_line("changed", iter_old->line_no,
iter_old->line, -1, NULL);
iter_old->line, -1, NULL, 0);
else if (iter_new)
print_ssdiff_line("changed", -1, NULL,
iter_new->line_no, iter_new->line);
iter_new->line_no, iter_new->line, 0);
if (iter_old) {
tmp = iter_old->next;
free(iter_old);
@ -202,14 +301,12 @@ void cgit_ssdiff_print_deferred_lines()
{
if (!deferred_old && !deferred_new)
return;
if (deferred_old && !deferred_new)
print_deferred_old_lines();
else if (!deferred_old && deferred_new)
print_deferred_new_lines();
else
print_deferred_changed_lines();
deferred_old = deferred_old_last = NULL;
deferred_new = deferred_new_last = NULL;
}
@ -220,9 +317,7 @@ void cgit_ssdiff_print_deferred_lines()
void cgit_ssdiff_line_cb(char *line, int len)
{
char c = line[len - 1];
line[len - 1] = '\0';
if (line[0] == '@') {
current_old_line = line_from_hunk(line, '-');
current_new_line = line_from_hunk(line, '+');
@ -232,7 +327,7 @@ void cgit_ssdiff_line_cb(char *line, int len)
if (deferred_old || deferred_new)
cgit_ssdiff_print_deferred_lines();
print_ssdiff_line("ctx", current_old_line, line,
current_new_line, line);
current_new_line, line, 0);
current_old_line += 1;
current_new_line += 1;
} else if (line[0] == '+') {