Initial revision of "git", the information manager from hell

1 files changed, 172 insertions, 0 deletions

diff --git a/commit-tree.c b/commit-tree.c
new file mode 100644
index 0000000..840307a
--- /dev/null
+++ b/commit-tree.c
@@ -0,0 +1,172 @@
+#include "cache.h"
+
+#include <pwd.h>
+#include <time.h>
+
+#define BLOCKING (1ul << 14)
+#define ORIG_OFFSET (40)
+
+/*
+ * Leave space at the beginning to insert the tag
+ * once we know how big things are.
+ *
+ * FIXME! Share the code with "write-tree.c"
+ */
+static void init_buffer(char **bufp, unsigned int *sizep)
+{
+	char *buf = malloc(BLOCKING);
+	memset(buf, 0, ORIG_OFFSET);
+	*sizep = ORIG_OFFSET;
+	*bufp = buf;
+}
+
+static void add_buffer(char **bufp, unsigned int *sizep, const char *fmt, ...)
+{
+	char one_line[2048];
+	va_list args;
+	int len;
+	unsigned long alloc, size, newsize;
+	char *buf;
+
+	va_start(args, fmt);
+	len = vsnprintf(one_line, sizeof(one_line), fmt, args);
+	va_end(args);
+	size = *sizep;
+	newsize = size + len;
+	alloc = (size + 32767) & ~32767;
+	buf = *bufp;
+	if (newsize > alloc) {
+		alloc = (newsize + 32767) & ~32767;   
+		buf = realloc(buf, alloc);
+		*bufp = buf;
+	}
+	*sizep = newsize;
+	memcpy(buf + size, one_line, len);
+}
+
+static int prepend_integer(char *buffer, unsigned val, int i)
+{
+	buffer[--i] = '\0';
+	do {
+		buffer[--i] = '0' + (val % 10);
+		val /= 10;
+	} while (val);
+	return i;
+}
+
+static void finish_buffer(char *tag, char **bufp, unsigned int *sizep)
+{
+	int taglen;
+	int offset;
+	char *buf = *bufp;
+	unsigned int size = *sizep;
+
+	offset = prepend_integer(buf, size - ORIG_OFFSET, ORIG_OFFSET);
+	taglen = strlen(tag);
+	offset -= taglen;
+	buf += offset;
+	size -= offset;
+	memcpy(buf, tag, taglen);
+
+	*bufp = buf;
+	*sizep = size;
+}
+
+static void remove_special(char *p)
+{
+	char c;
+	char *dst = p;
+
+	for (;;) {
+		c = *p;
+		p++;
+		switch(c) {
+		case '\n': case '<': case '>':
+			continue;
+		}
+		*dst++ = c;
+		if (!c)
+			break;
+	}
+}
+
+/*
+ * Having more than two parents may be strange, but hey, there's
+ * no conceptual reason why the file format couldn't accept multi-way
+ * merges. It might be the "union" of several packages, for example.
+ *
+ * I don't really expect that to happen, but this is here to make
+ * it clear that _conceptually_ it's ok..
+ */
+#define MAXPARENT (16)
+
+int main(int argc, char **argv)
+{
+	int i, len;
+	int parents = 0;
+	unsigned char tree_sha1[20];
+	unsigned char parent_sha1[MAXPARENT][20];
+	char *gecos, *realgecos;
+	char *email, realemail[1000];
+	char *date, *realdate;
+	char comment[1000];
+	struct passwd *pw;
+	time_t now;
+	char *buffer;
+	unsigned int size;
+
+	if (argc < 2 || get_sha1_hex(argv[1], tree_sha1) < 0)
+		usage("commit-tree <sha1> [-p <sha1>]* < changelog");
+
+	for (i = 2; i < argc; i += 2) {
+		char *a, *b;
+		a = argv[i]; b = argv[i+1];
+		if (!b || strcmp(a, "-p") || get_sha1_hex(b, parent_sha1[parents]))
+			usage("commit-tree <sha1> [-p <sha1>]* < changelog");
+		parents++;
+	}
+	if (!parents)
+		fprintf(stderr, "Committing initial tree %s\n", argv[1]);
+	pw = getpwuid(getuid());
+	if (!pw)
+		usage("You don't exist. Go away!");
+	realgecos = pw->pw_gecos;
+	len = strlen(pw->pw_name);
+	memcpy(realemail, pw->pw_name, len);
+	realemail[len] = '@';
+	gethostname(realemail+len+1, sizeof(realemail)-len-1);
+	time(&now);
+	realdate = ctime(&now);
+
+	gecos = getenv("COMMITTER_NAME") ? : realgecos;
+	email = getenv("COMMITTER_EMAIL") ? : realemail;
+	date = getenv("COMMITTER_DATE") ? : realdate;
+
+	remove_special(gecos); remove_special(realgecos);
+	remove_special(email); remove_special(realemail);
+	remove_special(date); remove_special(realdate);
+
+	init_buffer(&buffer, &size);
+	add_buffer(&buffer, &size, "tree %s\n", sha1_to_hex(tree_sha1));
+
+	/*
+	 * NOTE! This ordering means that the same exact tree merged with a
+	 * different order of parents will be a _different_ changeset even
+	 * if everything else stays the same.
+	 */
+	for (i = 0; i < parents; i++)
+		add_buffer(&buffer, &size, "parent %s\n", sha1_to_hex(parent_sha1[i]));
+
+	/* Person/date information */
+	add_buffer(&buffer, &size, "author %s <%s> %s\n", gecos, email, date);
+	add_buffer(&buffer, &size, "committer %s <%s> %s\n\n", realgecos, realemail, realdate);
+
+	/* And add the comment */
+	while (fgets(comment, sizeof(comment), stdin) != NULL)
+		add_buffer(&buffer, &size, "%s", comment);
+
+	finish_buffer("commit ", &buffer, &size);
+
+	write_sha1_file(buffer, size);
+	return 0;
+}