X-Git-Url: https://git.cameronkatri.com/cgit.git/blobdiff_plain/40e174d5364910750413d94b5417e57d108190ef..d3756bd7b00f9ad6adede3c7f956a25b22a2254a:/ui-ssdiff.c

diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 3591ab4..d183d40 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -1,10 +1,13 @@
 #include "cgit.h"
+#include "ui-ssdiff.h"
 #include "html.h"
 #include "ui-shared.h"
+#include "ui-diff.h"
 
 extern int use_ssdiff;
 
 static int current_old_line, current_new_line;
+static int **L = NULL;
 
 struct deferred_lines {
 	int line_no;
@@ -15,6 +18,77 @@ struct deferred_lines {
 static struct deferred_lines *deferred_old, *deferred_old_last;
 static struct deferred_lines *deferred_new, *deferred_new_last;
 
+static void create_or_reset_lcs_table(void)
+{
+	int i;
+
+	if (L != NULL) {
+		memset(*L, 0, sizeof(int) * MAX_SSDIFF_SIZE);
+		return;
+	}
+
+	// xcalloc will die if we ran out of memory;
+	// not very helpful for debugging
+	L = (int**)xcalloc(MAX_SSDIFF_M, sizeof(int *));
+	*L = (int*)xcalloc(MAX_SSDIFF_SIZE, sizeof(int));
+
+	for (i = 1; i < MAX_SSDIFF_M; i++) {
+		L[i] = *L + i * MAX_SSDIFF_N;
+	}
+}
+
+static char *longest_common_subsequence(char *A, char *B)
+{
+	int i, j, ri;
+	int m = strlen(A);
+	int n = strlen(B);
+	int tmp1, tmp2;
+	int lcs_length;
+	char *result;
+
+	// We bail if the lines are too long
+	if (m >= MAX_SSDIFF_M || n >= MAX_SSDIFF_N)
+		return NULL;
+
+	create_or_reset_lcs_table();
+
+	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;
@@ -40,9 +114,9 @@ static char *replace_tabs(char *line)
 {
 	char *prev_buf = line;
 	char *cur_buf;
-        int linelen = strlen(line);
+	int linelen = strlen(line);
 	int n_tabs = 0;
-        int i;
+	int i;
 	char *result;
 	char *spaces = "        ";
 
@@ -52,10 +126,10 @@ static char *replace_tabs(char *line)
 		return result;
 	}
 
-        for (i = 0; i < linelen; i++)
+	for (i = 0; i < linelen; i++)
 		if (line[i] == '\t')
 			n_tabs += 1;
-        result = xmalloc(linelen + n_tabs * 8 + 1);
+	result = xmalloc(linelen + n_tabs * 8 + 1);
 	result[0] = '\0';
 
 	while (1) {
@@ -64,15 +138,25 @@ static char *replace_tabs(char *line)
 			strcat(result, prev_buf);
 			break;
 		} else {
-			strcat(result, " ");
-			strncat(result, spaces, 8 - (strlen(result) % 8));
 			strncat(result, prev_buf, cur_buf - prev_buf);
+			strncat(result, spaces, 8 - (strlen(result) % 8));
 		}
 		prev_buf = cur_buf + 1;
 	}
 	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));
@@ -101,70 +185,133 @@ 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)
 {
-	html("<tr>");
-	if (old_line_no > 0)
-		htmlf("<td class='%s'>%d </td><td class='%s'>", class,
-		      old_line_no, class);
-	else
-		htmlf("<td class='%s_dark'>  </td><td class='%s_dark'>", class, class);
-
-	if (old_line) {
-		old_line = replace_tabs(old_line + 1);
-		html_txt(old_line);
-		free(old_line);
+	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);
 	}
+}
 
-	html("  </td>");
+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 (new_line_no > 0)
-		htmlf("<td class='%s'>  %d </td><td class='%s'>", class,
-		      new_line_no, class);
+	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>\n");
+	if (old_line_no > 0) {
+		struct diff_filespec *old_file = cgit_get_current_old_file();
+		char *lineno_str = fmt("n%d", old_line_no);
+		char *id_str = fmt("id=%s#%s", is_null_sha1(old_file->sha1)?"HEAD":sha1_to_hex(old_rev_sha1), lineno_str);
+		char *fileurl = cgit_fileurl(ctx.repo->url, "tree", old_file->path, id_str);
+		html("<td class='lineno'><a href='");
+		html(fileurl);
+		htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
+		html("</td>");
+		htmlf("<td class='%s'>", class);
+		free(fileurl);
+	} else if (old_line)
+		htmlf("<td class='lineno'></td><td class='%s'>", class);
 	else
-		htmlf("<td class='%s_dark'>  </td><td class='%s_dark'>", class, class);
+		htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
+	if (old_line) {
+		if (lcs)
+			print_part_with_lcs("del", old_line, lcs);
+		else
+			html_txt(old_line);
+	}
 
+	html("</td>\n");
+	if (new_line_no > 0) {
+		struct diff_filespec *new_file = cgit_get_current_new_file();
+		char *lineno_str = fmt("n%d", new_line_no);
+		char *id_str = fmt("id=%s#%s", is_null_sha1(new_file->sha1)?"HEAD":sha1_to_hex(new_rev_sha1), lineno_str);
+		char *fileurl = cgit_fileurl(ctx.repo->url, "tree", new_file->path, id_str);
+		html("<td class='lineno'><a href='");
+		html(fileurl);
+		htmlf("' id='%s'>%s</a>", lineno_str, lineno_str + 1);
+		html("</td>");
+		htmlf("<td class='%s'>", class);
+		free(fileurl);
+	} else if (new_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()
+static void print_deferred_old_lines(void)
 {
 	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;
 	}
 }
 
-static void print_deferred_new_lines()
+static void print_deferred_new_lines(void)
 {
 	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;
 	}
 }
 
-static void print_deferred_changed_lines()
+static void print_deferred_changed_lines(void)
 {
 	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;
@@ -172,14 +319,14 @@ 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);
@@ -194,18 +341,16 @@ static void print_deferred_changed_lines()
 	}
 }
 
-void cgit_ssdiff_print_deferred_lines()
+void cgit_ssdiff_print_deferred_lines(void)
 {
 	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;
 }
@@ -216,9 +361,7 @@ 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, '+');
@@ -228,7 +371,7 @@ 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] == '+') {
@@ -249,16 +392,22 @@ void cgit_ssdiff_line_cb(char *line, int len)
 	line[len - 1] = c;
 }
 
-void cgit_ssdiff_header()
+void cgit_ssdiff_header_begin(void)
+{
+	current_old_line = -1;
+	current_new_line = -1;
+	html("<tr><td class='space' colspan='4'><div></div></td></tr>");
+	html("<tr><td class='head' colspan='4'>");
+}
+
+void cgit_ssdiff_header_end(void)
 {
-	current_old_line = 0;
-	current_new_line = 0;
-	html("<table class='ssdiff'>");
+	html("</td><tr>");
 }
 
-void cgit_ssdiff_footer()
+void cgit_ssdiff_footer(void)
 {
 	if (deferred_old || deferred_new)
 		cgit_ssdiff_print_deferred_lines();
-	html("</table>");
+	html("<tr><td class='foot' colspan='4'></td></tr>");
 }