cache support (-c option)

"Optionally the -c cachefile option can be used to cache the entries of
the log page up to the point of the last commit. The cachefile will store
the last commit id and the entries in the HTML table."

this caches the diffstat and commits, it is an expensive operation (twss).

1 files changed, 113 insertions, 38 deletions

diff --git a/stagit.c b/stagit.c
index 7c52778..158447d 100644
--- a/stagit.c
+++ b/stagit.c
@@ -58,6 +58,12 @@ static char description[255];
 static char cloneurl[1024];
 static int haslicense, hasreadme, hassubmodules;
 
+/* cache */
+static git_oid lastoid;
+static char lastoidstr[GIT_OID_HEXSZ + 2]; /* id + newline + nul byte */
+static FILE *rcachefp, *wcachefp;
+static const char *cachefile;
+
 void
 deltainfo_free(struct deltainfo *di)
 {
@@ -530,13 +536,43 @@ printshowfile(FILE *fp, struct commitinfo *ci)
 	}
 }
 
+void
+writelogline(FILE *fp, struct commitinfo *ci)
+{
+	size_t len;
+
+	fputs("<tr><td>", fp);
+	if (ci->author)
+		printtimeshort(fp, &(ci->author->when));
+	fputs("</td><td>", fp);
+	if (ci->summary) {
+		fprintf(fp, "<a href=\"%scommit/%s.html\">", relpath, ci->oid);
+		if ((len = strlen(ci->summary)) > summarylen) {
+			xmlencode(fp, ci->summary, summarylen - 1);
+			fputs("…", fp);
+		} else {
+			xmlencode(fp, ci->summary, len);
+		}
+		fputs("</a>", fp);
+	}
+	fputs("</td><td>", fp);
+	if (ci->author)
+		xmlencode(fp, ci->author->name, strlen(ci->author->name));
+	fputs("</td><td class=\"num\">", fp);
+	fprintf(fp, "%zu", ci->filecount);
+	fputs("</td><td class=\"num\">", fp);
+	fprintf(fp, "+%zu", ci->addcount);
+	fputs("</td><td class=\"num\">", fp);
+	fprintf(fp, "-%zu", ci->delcount);
+	fputs("</td></tr>\n", fp);
+}
+
 int
 writelog(FILE *fp, const git_oid *oid)
 {
 	struct commitinfo *ci;
 	git_revwalk *w = NULL;
 	git_oid id;
-	size_t len;
 	char path[PATH_MAX];
 	FILE *fpfile;
 	int r;
@@ -546,40 +582,17 @@ writelog(FILE *fp, const git_oid *oid)
 	git_revwalk_sorting(w, GIT_SORT_TIME);
 	git_revwalk_simplify_first_parent(w);
 
-	fputs("<table id=\"log\"><thead>\n<tr><td>Date</td><td>Commit message</td>"
-		  "<td>Author</td><td class=\"num\">Files</td><td class=\"num\">+</td>"
-		  "<td class=\"num\">-</td></tr>\n</thead><tbody>\n", fp);
-
 	while (!git_revwalk_next(&id, w)) {
 		relpath = "";
 
+		if (cachefile && !memcmp(&id, &lastoid, sizeof(id)))
+			break;
 		if (!(ci = commitinfo_getbyoid(&id)))
 			break;
 
-		fputs("<tr><td>", fp);
-		if (ci->author)
-			printtimeshort(fp, &(ci->author->when));
-		fputs("</td><td>", fp);
-		if (ci->summary) {
-			fprintf(fp, "<a href=\"%scommit/%s.html\">", relpath, ci->oid);
-			if ((len = strlen(ci->summary)) > summarylen) {
-				xmlencode(fp, ci->summary, summarylen - 1);
-				fputs("…", fp);
-			} else {
-				xmlencode(fp, ci->summary, len);
-			}
-			fputs("</a>", fp);
-		}
-		fputs("</td><td>", fp);
-		if (ci->author)
-			xmlencode(fp, ci->author->name, strlen(ci->author->name));
-		fputs("</td><td class=\"num\">", fp);
-		fprintf(fp, "%zu", ci->filecount);
-		fputs("</td><td class=\"num\">", fp);
-		fprintf(fp, "+%zu", ci->addcount);
-		fputs("</td><td class=\"num\">", fp);
-		fprintf(fp, "-%zu", ci->delcount);
-		fputs("</td></tr>\n", fp);
+		writelogline(fp, ci);
+		if (cachefile)
+			writelogline(wcachefp, ci);
 
 		relpath = "../";
 
@@ -599,8 +612,6 @@ writelog(FILE *fp, const git_oid *oid)
 		}
 		commitinfo_free(ci);
 	}
-	fputs("</tbody></table>", fp);
-
 	git_revwalk_free(w);
 
 	relpath = "";
@@ -1005,6 +1016,13 @@ joinpath(char *buf, size_t bufsiz, const char *path, const char *path2)
 			path, path[0] && path[strlen(path) - 1] != '/' ? "/" : "", path2);
 }
 
+void
+usage(char *argv0)
+{
+	fprintf(stderr, "%s [-c cachefile] repodir\n", argv0);
+	exit(1);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -1013,12 +1031,23 @@ main(int argc, char *argv[])
 	const git_error *e = NULL;
 	FILE *fp, *fpread;
 	char path[PATH_MAX], repodirabs[PATH_MAX + 1], *p;
-
-	if (argc != 2) {
-		fprintf(stderr, "%s <repodir>\n", argv[0]);
-		return 1;
+	char tmppath[64] = "cache.XXXXXXXXXXXX", buf[BUFSIZ];
+	size_t n;
+	int i, fd;
+
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] != '-') {
+			if (repodir)
+				usage(argv[0]);
+			repodir = argv[i];
+		} else if (argv[i][1] == 'c') {
+			if (i + 1 >= argc)
+				usage(argv[0]);
+			cachefile = argv[++i];
+		}
 	}
-	repodir = argv[1];
+	if (!repodir)
+		usage(argv[0]);
 
 	if (!realpath(repodir, repodirabs))
 		err(1, "realpath");
@@ -1088,9 +1117,51 @@ main(int argc, char *argv[])
 	/* log for HEAD */
 	fp = efopen("log.html", "w");
 	relpath = "";
-	writeheader(fp, "Log");
 	mkdir("commit", 0755);
-	writelog(fp, head);
+	writeheader(fp, "Log");
+	fputs("<table id=\"log\"><thead>\n<tr><td>Date</td><td>Commit message</td>"
+		  "<td>Author</td><td class=\"num\">Files</td><td class=\"num\">+</td>"
+		  "<td class=\"num\">-</td></tr>\n</thead><tbody>\n", fp);
+
+	if (cachefile) {
+		/* read from cache file (does not need to exist) */
+		if ((rcachefp = fopen(cachefile, "r"))) {
+			if (!fgets(lastoidstr, sizeof(lastoidstr), rcachefp))
+				errx(1, "%s: no object id", cachefile);
+			if (git_oid_fromstr(&lastoid, lastoidstr))
+				errx(1, "%s: invalid object id", cachefile);
+		}
+
+		/* write log to (temporary) cache */
+		if ((fd = mkstemp(tmppath)) == -1)
+			err(1, "mkstemp");
+		if (!(wcachefp = fdopen(fd, "w")))
+			err(1, "fdopen");
+		/* write last commit id (HEAD) */
+		git_oid_tostr(buf, sizeof(buf), head);
+		fprintf(wcachefp, "%s\n", buf);
+
+		writelog(fp, head);
+
+		if (rcachefp) {
+			/* append previous log to log.html and the new cache */
+			while (!feof(rcachefp)) {
+				n = fread(buf, 1, sizeof(buf), rcachefp);
+				if (ferror(rcachefp))
+					err(1, "fread");
+				if (fwrite(buf, 1, n, fp) != n)
+					err(1, "fwrite");
+				if (fwrite(buf, 1, n, wcachefp) != n)
+					err(1, "fwrite");
+			}
+			fclose(rcachefp);
+		}
+		fclose(wcachefp);
+	} else {
+		writelog(fp, head);
+	}
+
+	fputs("</tbody></table>", fp);
 	writefooter(fp);
 	fclose(fp);
 
@@ -1113,6 +1184,10 @@ main(int argc, char *argv[])
 	writeatom(fp);
 	fclose(fp);
 
+	/* rename new cache file on success */
+	if (cachefile && rename(tmppath, cachefile))
+		err(1, "rename: '%s' to '%s'", tmppath, cachefile);
+
 	/* cleanup */
 	git_repository_free(repo);
 	git_libgit2_shutdown();