Make git-mailinfo a builtin

[jc: with a bit of constness tightening]

Signed-off-by: Lukas Sandström <lukass@etek.chalmers.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 846 insertions, 0 deletions

diff --git a/builtin-mailinfo.c b/builtin-mailinfo.c
new file mode 100644
index 000000000..821642a7a
--- /dev/null
+++ b/builtin-mailinfo.c
@@ -0,0 +1,846 @@
+/*
+ * Another stupid program, this one parsing the headers of an
+ * email to figure out authorship and subject
+ */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#ifndef NO_ICONV
+#include <iconv.h>
+#endif
+#include "git-compat-util.h"
+#include "cache.h"
+#include "builtin.h"
+
+static FILE *cmitmsg, *patchfile, *fin, *fout;
+
+static int keep_subject = 0;
+static const char *metainfo_charset = NULL;
+static char line[1000];
+static char date[1000];
+static char name[1000];
+static char email[1000];
+static char subject[1000];
+
+static enum  {
+	TE_DONTCARE, TE_QP, TE_BASE64,
+} transfer_encoding;
+static char charset[256];
+
+static char multipart_boundary[1000];
+static int multipart_boundary_len;
+static int patch_lines = 0;
+
+static char *sanity_check(char *name, char *email)
+{
+	int len = strlen(name);
+	if (len < 3 || len > 60)
+		return email;
+	if (strchr(name, '@') || strchr(name, '<') || strchr(name, '>'))
+		return email;
+	return name;
+}
+
+static int bogus_from(char *line)
+{
+	/* John Doe <johndoe> */
+	char *bra, *ket, *dst, *cp;
+
+	/* This is fallback, so do not bother if we already have an
+	 * e-mail address.
+	 */
+	if (*email)
+		return 0;
+
+	bra = strchr(line, '<');
+	if (!bra)
+		return 0;
+	ket = strchr(bra, '>');
+	if (!ket)
+		return 0;
+
+	for (dst = email, cp = bra+1; cp < ket; )
+		*dst++ = *cp++;
+	*dst = 0;
+	for (cp = line; isspace(*cp); cp++)
+		;
+	for (bra--; isspace(*bra); bra--)
+		*bra = 0;
+	cp = sanity_check(cp, email);
+	strcpy(name, cp);
+	return 1;
+}
+
+static int handle_from(char *in_line)
+{
+	char line[1000];
+	char *at;
+	char *dst;
+
+	strcpy(line, in_line);
+	at = strchr(line, '@');
+	if (!at)
+		return bogus_from(line);
+
+	/*
+	 * If we already have one email, don't take any confusing lines
+	 */
+	if (*email && strchr(at+1, '@'))
+		return 0;
+
+	/* Pick up the string around '@', possibly delimited with <>
+	 * pair; that is the email part.  White them out while copying.
+	 */
+	while (at > line) {
+		char c = at[-1];
+		if (isspace(c))
+			break;
+		if (c == '<') {
+			at[-1] = ' ';
+			break;
+		}
+		at--;
+	}
+	dst = email;
+	for (;;) {
+		unsigned char c = *at;
+		if (!c || c == '>' || isspace(c)) {
+			if (c == '>')
+				*at = ' ';
+			break;
+		}
+		*at++ = ' ';
+		*dst++ = c;
+	}
+	*dst++ = 0;
+
+	/* The remainder is name.  It could be "John Doe <john.doe@xz>"
+	 * or "john.doe@xz (John Doe)", but we have whited out the
+	 * email part, so trim from both ends, possibly removing
+	 * the () pair at the end.
+	 */
+	at = line + strlen(line);
+	while (at > line) {
+		unsigned char c = *--at;
+		if (!isspace(c)) {
+			at[(c == ')') ? 0 : 1] = 0;
+			break;
+		}
+	}
+
+	at = line;
+	for (;;) {
+		unsigned char c = *at;
+		if (!c || !isspace(c)) {
+			if (c == '(')
+				at++;
+			break;
+		}
+		at++;
+	}
+	at = sanity_check(at, email);
+	strcpy(name, at);
+	return 1;
+}
+
+static int handle_date(char *line)
+{
+	strcpy(date, line);
+	return 0;
+}
+
+static int handle_subject(char *line)
+{
+	strcpy(subject, line);
+	return 0;
+}
+
+/* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
+ * to have enough heuristics to grok MIME encoded patches often found
+ * on our mailing lists.  For example, we do not even treat header lines
+ * case insensitively.
+ */
+
+static int slurp_attr(const char *line, const char *name, char *attr)
+{
+	char *ends, *ap = strcasestr(line, name);
+	size_t sz;
+
+	if (!ap) {
+		*attr = 0;
+		return 0;
+	}
+	ap += strlen(name);
+	if (*ap == '"') {
+		ap++;
+		ends = "\"";
+	}
+	else
+		ends = "; \t";
+	sz = strcspn(ap, ends);
+	memcpy(attr, ap, sz);
+	attr[sz] = 0;
+	return 1;
+}
+
+static int handle_subcontent_type(char *line)
+{
+	/* We do not want to mess with boundary.  Note that we do not
+	 * handle nested multipart.
+	 */
+	if (strcasestr(line, "boundary=")) {
+		fprintf(stderr, "Not handling nested multipart message.\n");
+		exit(1);
+	}
+	slurp_attr(line, "charset=", charset);
+	if (*charset) {
+		int i, c;
+		for (i = 0; (c = charset[i]) != 0; i++)
+			charset[i] = tolower(c);
+	}
+	return 0;
+}
+
+static int handle_content_type(char *line)
+{
+	*multipart_boundary = 0;
+	if (slurp_attr(line, "boundary=", multipart_boundary + 2)) {
+		memcpy(multipart_boundary, "--", 2);
+		multipart_boundary_len = strlen(multipart_boundary);
+	}
+	slurp_attr(line, "charset=", charset);
+	return 0;
+}
+
+static int handle_content_transfer_encoding(char *line)
+{
+	if (strcasestr(line, "base64"))
+		transfer_encoding = TE_BASE64;
+	else if (strcasestr(line, "quoted-printable"))
+		transfer_encoding = TE_QP;
+	else
+		transfer_encoding = TE_DONTCARE;
+	return 0;
+}
+
+static int is_multipart_boundary(const char *line)
+{
+	return (!memcmp(line, multipart_boundary, multipart_boundary_len));
+}
+
+static int eatspace(char *line)
+{
+	int len = strlen(line);
+	while (len > 0 && isspace(line[len-1]))
+		line[--len] = 0;
+	return len;
+}
+
+#define SEEN_FROM 01
+#define SEEN_DATE 02
+#define SEEN_SUBJECT 04
+#define SEEN_BOGUS_UNIX_FROM 010
+#define SEEN_PREFIX  020
+
+/* First lines of body can have From:, Date:, and Subject: or empty */
+static void handle_inbody_header(int *seen, char *line)
+{
+	if (*seen & SEEN_PREFIX)
+		return;
+	if (isspace(*line)) {
+		char *cp;
+		for (cp = line + 1; *cp; cp++) {
+			if (!isspace(*cp))
+				break;
+		}
+		if (!*cp)
+			return;
+	}
+	if (!memcmp(">From", line, 5) && isspace(line[5])) {
+		if (!(*seen & SEEN_BOGUS_UNIX_FROM)) {
+			*seen |= SEEN_BOGUS_UNIX_FROM;
+			return;
+		}
+	}
+	if (!memcmp("From:", line, 5) && isspace(line[5])) {
+		if (!(*seen & SEEN_FROM) && handle_from(line+6)) {
+			*seen |= SEEN_FROM;
+			return;
+		}
+	}
+	if (!memcmp("Date:", line, 5) && isspace(line[5])) {
+		if (!(*seen & SEEN_DATE)) {
+			handle_date(line+6);
+			*seen |= SEEN_DATE;
+			return;
+		}
+	}
+	if (!memcmp("Subject:", line, 8) && isspace(line[8])) {
+		if (!(*seen & SEEN_SUBJECT)) {
+			handle_subject(line+9);
+			*seen |= SEEN_SUBJECT;
+			return;
+		}
+	}
+	if (!memcmp("[PATCH]", line, 7) && isspace(line[7])) {
+		if (!(*seen & SEEN_SUBJECT)) {
+			handle_subject(line);
+			*seen |= SEEN_SUBJECT;
+			return;
+		}
+	}
+	*seen |= SEEN_PREFIX;
+}
+
+static char *cleanup_subject(char *subject)
+{
+	if (keep_subject)
+		return subject;
+	for (;;) {
+		char *p;
+		int len, remove;
+		switch (*subject) {
+		case 'r': case 'R':
+			if (!memcmp("e:", subject+1, 2)) {
+				subject +=3;
+				continue;
+			}
+			break;
+		case ' ': case '\t': case ':':
+			subject++;
+			continue;
+
+		case '[':
+			p = strchr(subject, ']');
+			if (!p) {
+				subject++;
+				continue;
+			}
+			len = strlen(p);
+			remove = p - subject;
+			if (remove <= len *2) {
+				subject = p+1;
+				continue;
+			}
+			break;
+		}
+		eatspace(subject);
+		return subject;
+	}
+}
+
+static void cleanup_space(char *buf)
+{
+	unsigned char c;
+	while ((c = *buf) != 0) {
+		buf++;
+		if (isspace(c)) {
+			buf[-1] = ' ';
+			c = *buf;
+			while (isspace(c)) {
+				int len = strlen(buf);
+				memmove(buf, buf+1, len);
+				c = *buf;
+			}
+		}
+	}
+}
+
+static void decode_header_bq(char *it);
+typedef int (*header_fn_t)(char *);
+struct header_def {
+	const char *name;
+	header_fn_t func;
+	int namelen;
+};
+
+static void check_header(char *line, struct header_def *header)
+{
+	int i;
+
+	if (header[0].namelen <= 0) {
+		for (i = 0; header[i].name; i++)
+			header[i].namelen = strlen(header[i].name);
+	}
+	for (i = 0; header[i].name; i++) {
+		int len = header[i].namelen;
+		if (!strncasecmp(line, header[i].name, len) &&
+		    line[len] == ':' && isspace(line[len + 1])) {
+			/* Unwrap inline B and Q encoding, and optionally
+			 * normalize the meta information to utf8.
+			 */
+			decode_header_bq(line + len + 2);
+			header[i].func(line + len + 2);
+			break;
+		}
+	}
+}
+
+static void check_subheader_line(char *line)
+{
+	static struct header_def header[] = {
+		{ "Content-Type", handle_subcontent_type },
+		{ "Content-Transfer-Encoding",
+		  handle_content_transfer_encoding },
+		{ NULL },
+	};
+	check_header(line, header);
+}
+static void check_header_line(char *line)
+{
+	static struct header_def header[] = {
+		{ "From", handle_from },
+		{ "Date", handle_date },
+		{ "Subject", handle_subject },
+		{ "Content-Type", handle_content_type },
+		{ "Content-Transfer-Encoding",
+		  handle_content_transfer_encoding },
+		{ NULL },
+	};
+	check_header(line, header);
+}
+
+static int is_rfc2822_header(char *line)
+{
+	/*
+	 * The section that defines the loosest possible
+	 * field name is "3.6.8 Optional fields".
+	 *
+	 * optional-field = field-name ":" unstructured CRLF
+	 * field-name = 1*ftext
+	 * ftext = %d33-57 / %59-126
+	 */
+	int ch;
+	char *cp = line;
+	while ((ch = *cp++)) {
+		if (ch == ':')
+			return cp != line;
+		if ((33 <= ch && ch <= 57) ||
+		    (59 <= ch && ch <= 126))
+			continue;
+		break;
+	}
+	return 0;
+}
+
+static int read_one_header_line(char *line, int sz, FILE *in)
+{
+	int ofs = 0;
+	while (ofs < sz) {
+		int peek, len;
+		if (fgets(line + ofs, sz - ofs, in) == NULL)
+			break;
+		len = eatspace(line + ofs);
+		if ((len == 0) || !is_rfc2822_header(line)) {
+			/* Re-add the newline */
+			line[ofs + len] = '\n';
+			line[ofs + len + 1] = '\0';
+			break;
+		}
+		ofs += len;
+		/* Yuck, 2822 header "folding" */
+		peek = fgetc(in); ungetc(peek, in);
+		if (peek != ' ' && peek != '\t')
+			break;
+	}
+	/* Count mbox From headers as headers */
+	if (!ofs && !memcmp(line, "From ", 5))
+		ofs = 1;
+	return ofs;
+}
+
+static unsigned hexval(int c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	if (c >= 'A' && c <= 'F')
+		return c - 'A' + 10;
+	return ~0;
+}
+
+static int decode_q_segment(char *in, char *ot, char *ep, int rfc2047)
+{
+	int c;
+	while ((c = *in++) != 0 && (in <= ep)) {
+		if (c == '=') {
+			int d = *in++;
+			if (d == '\n' || !d)
+				break; /* drop trailing newline */
+			*ot++ = ((hexval(d) << 4) | hexval(*in++));
+			continue;
+		}
+		if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
+			c = 0x20;
+		*ot++ = c;
+	}
+	*ot = 0;
+	return 0;
+}
+
+static int decode_b_segment(char *in, char *ot, char *ep)
+{
+	/* Decode in..ep, possibly in-place to ot */
+	int c, pos = 0, acc = 0;
+
+	while ((c = *in++) != 0 && (in <= ep)) {
+		if (c == '+')
+			c = 62;
+		else if (c == '/')
+			c = 63;
+		else if ('A' <= c && c <= 'Z')
+			c -= 'A';
+		else if ('a' <= c && c <= 'z')
+			c -= 'a' - 26;
+		else if ('0' <= c && c <= '9')
+			c -= '0' - 52;
+		else if (c == '=') {
+			/* padding is almost like (c == 0), except we do
+			 * not output NUL resulting only from it;
+			 * for now we just trust the data.
+			 */
+			c = 0;
+		}
+		else
+			continue; /* garbage */
+		switch (pos++) {
+		case 0:
+			acc = (c << 2);
+			break;
+		case 1:
+			*ot++ = (acc | (c >> 4));
+			acc = (c & 15) << 4;
+			break;
+		case 2:
+			*ot++ = (acc | (c >> 2));
+			acc = (c & 3) << 6;
+			break;
+		case 3:
+			*ot++ = (acc | c);
+			acc = pos = 0;
+			break;
+		}
+	}
+	*ot = 0;
+	return 0;
+}
+
+static void convert_to_utf8(char *line, char *charset)
+{
+#ifndef NO_ICONV
+	char *in, *out;
+	size_t insize, outsize, nrc;
+	char outbuf[4096]; /* cheat */
+	static char latin_one[] = "latin1";
+	char *input_charset = *charset ? charset : latin_one;
+	iconv_t conv = iconv_open(metainfo_charset, input_charset);
+
+	if (conv == (iconv_t) -1) {
+		static int warned_latin1_once = 0;
+		if (input_charset != latin_one) {
+			fprintf(stderr, "cannot convert from %s to %s\n",
+				input_charset, metainfo_charset);
+			*charset = 0;
+		}
+		else if (!warned_latin1_once) {
+			warned_latin1_once = 1;
+			fprintf(stderr, "tried to convert from %s to %s, "
+				"but your iconv does not work with it.\n",
+				input_charset, metainfo_charset);
+		}
+		return;
+	}
+	in = line;
+	insize = strlen(in);
+	out = outbuf;
+	outsize = sizeof(outbuf);
+	nrc = iconv(conv, &in, &insize, &out, &outsize);
+	iconv_close(conv);
+	if (nrc == (size_t) -1)
+		return;
+	*out = 0;
+	strcpy(line, outbuf);
+#endif
+}
+
+static void decode_header_bq(char *it)
+{
+	char *in, *out, *ep, *cp, *sp;
+	char outbuf[1000];
+
+	in = it;
+	out = outbuf;
+	while ((ep = strstr(in, "=?")) != NULL) {
+		int sz, encoding;
+		char charset_q[256], piecebuf[256];
+		if (in != ep) {
+			sz = ep - in;
+			memcpy(out, in, sz);
+			out += sz;
+			in += sz;
+		}
+		/* E.g.
+		 * ep : "=?iso-2022-jp?B?GyR...?= foo"
+		 * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
+		 */
+		ep += 2;
+		cp = strchr(ep, '?');
+		if (!cp)
+			return; /* no munging */
+		for (sp = ep; sp < cp; sp++)
+			charset_q[sp - ep] = tolower(*sp);
+		charset_q[cp - ep] = 0;
+		encoding = cp[1];
+		if (!encoding || cp[2] != '?')
+			return; /* no munging */
+		ep = strstr(cp + 3, "?=");
+		if (!ep)
+			return; /* no munging */
+		switch (tolower(encoding)) {
+		default:
+			return; /* no munging */
+		case 'b':
+			sz = decode_b_segment(cp + 3, piecebuf, ep);
+			break;
+		case 'q':
+			sz = decode_q_segment(cp + 3, piecebuf, ep, 1);
+			break;
+		}
+		if (sz < 0)
+			return;
+		if (metainfo_charset)
+			convert_to_utf8(piecebuf, charset_q);
+		strcpy(out, piecebuf);
+		out += strlen(out);
+		in = ep + 2;
+	}
+	strcpy(out, in);
+	strcpy(it, outbuf);
+}
+
+static void decode_transfer_encoding(char *line)
+{
+	char *ep;
+
+	switch (transfer_encoding) {
+	case TE_QP:
+		ep = line + strlen(line);
+		decode_q_segment(line, line, ep, 0);
+		break;
+	case TE_BASE64:
+		ep = line + strlen(line);
+		decode_b_segment(line, line, ep);
+		break;
+	case TE_DONTCARE:
+		break;
+	}
+}
+
+static void handle_info(void)
+{
+	char *sub;
+
+	sub = cleanup_subject(subject);
+	cleanup_space(name);
+	cleanup_space(date);
+	cleanup_space(email);
+	cleanup_space(sub);
+
+	fprintf(fout, "Author: %s\nEmail: %s\nSubject: %s\nDate: %s\n\n",
+	       name, email, sub, date);
+}
+
+/* We are inside message body and have read line[] already.
+ * Spit out the commit log.
+ */
+static int handle_commit_msg(int *seen)
+{
+	if (!cmitmsg)
+		return 0;
+	do {
+		if (!memcmp("diff -", line, 6) ||
+		    !memcmp("---", line, 3) ||
+		    !memcmp("Index: ", line, 7))
+			break;
+		if ((multipart_boundary[0] && is_multipart_boundary(line))) {
+			/* We come here when the first part had only
+			 * the commit message without any patch.  We
+			 * pretend we have not seen this line yet, and
+			 * go back to the loop.
+			 */
+			return 1;
+		}
+
+		/* Unwrap transfer encoding and optionally
+		 * normalize the log message to UTF-8.
+		 */
+		decode_transfer_encoding(line);
+		if (metainfo_charset)
+			convert_to_utf8(line, charset);
+
+		handle_inbody_header(seen, line);
+		if (!(*seen & SEEN_PREFIX))
+			continue;
+
+		fputs(line, cmitmsg);
+	} while (fgets(line, sizeof(line), fin) != NULL);
+	fclose(cmitmsg);
+	cmitmsg = NULL;
+	return 0;
+}
+
+/* We have done the commit message and have the first
+ * line of the patch in line[].
+ */
+static void handle_patch(void)
+{
+	do {
+		if (multipart_boundary[0] && is_multipart_boundary(line))
+			break;
+		/* Only unwrap transfer encoding but otherwise do not
+		 * do anything.  We do *NOT* want UTF-8 conversion
+		 * here; we are dealing with the user payload.
+		 */
+		decode_transfer_encoding(line);
+		fputs(line, patchfile);
+		patch_lines++;
+	} while (fgets(line, sizeof(line), fin) != NULL);
+}
+
+/* multipart boundary and transfer encoding are set up for us, and we
+ * are at the end of the sub header.  do equivalent of handle_body up
+ * to the next boundary without closing patchfile --- we will expect
+ * that the first part to contain commit message and a patch, and
+ * handle other parts as pure patches.
+ */
+static int handle_multipart_one_part(int *seen)
+{
+	int n = 0;
+
+	while (fgets(line, sizeof(line), fin) != NULL) {
+	again:
+		n++;
+		if (is_multipart_boundary(line))
+			break;
+		if (handle_commit_msg(seen))
+			goto again;
+		handle_patch();
+		break;
+	}
+	if (n == 0)
+		return -1;
+	return 0;
+}
+
+static void handle_multipart_body(void)
+{
+	int seen = 0;
+	int part_num = 0;
+
+	/* Skip up to the first boundary */
+	while (fgets(line, sizeof(line), fin) != NULL)
+		if (is_multipart_boundary(line)) {
+			part_num = 1;
+			break;
+		}
+	if (!part_num)
+		return;
+	/* We are on boundary line.  Start slurping the subhead. */
+	while (1) {
+		int hdr = read_one_header_line(line, sizeof(line), fin);
+		if (!hdr) {
+			if (handle_multipart_one_part(&seen) < 0)
+				return;
+			/* Reset per part headers */
+			transfer_encoding = TE_DONTCARE;
+			charset[0] = 0;
+		}
+		else
+			check_subheader_line(line);
+	}
+	fclose(patchfile);
+	if (!patch_lines) {
+		fprintf(stderr, "No patch found\n");
+		exit(1);
+	}
+}
+
+/* Non multipart message */
+static void handle_body(void)
+{
+	int seen = 0;
+
+	handle_commit_msg(&seen);
+	handle_patch();
+	fclose(patchfile);
+	if (!patch_lines) {
+		fprintf(stderr, "No patch found\n");
+		exit(1);
+	}
+}
+
+int mailinfo(FILE *in, FILE *out, int ks, const char *encoding,
+	     const char *msg, const char *patch)
+{
+	keep_subject = ks;
+	metainfo_charset = encoding;
+	fin = in;
+	fout = out;
+
+	cmitmsg = fopen(msg, "w");
+	if (!cmitmsg) {
+		perror(msg);
+		return -1;
+	}
+	patchfile = fopen(patch, "w");
+	if (!patchfile) {
+		perror(patch);
+		fclose(cmitmsg);
+		return -1;
+	}
+	while (1) {
+		int hdr = read_one_header_line(line, sizeof(line), fin);
+		if (!hdr) {
+			if (multipart_boundary[0])
+				handle_multipart_body();
+			else
+				handle_body();
+			handle_info();
+			break;
+		}
+		check_header_line(line);
+	}
+
+	return 0;
+}
+
+static const char mailinfo_usage[] =
+	"git-mailinfo [-k] [-u | --encoding=<encoding>] msg patch <mail >info";
+
+int cmd_mailinfo(int argc, const char **argv, char **envp)
+{
+	/* NEEDSWORK: might want to do the optional .git/ directory
+	 * discovery
+	 */
+	git_config(git_default_config);
+
+	while (1 < argc && argv[1][0] == '-') {
+		if (!strcmp(argv[1], "-k"))
+			keep_subject = 1;
+		else if (!strcmp(argv[1], "-u"))
+			metainfo_charset = git_commit_encoding;
+		else if (!strncmp(argv[1], "--encoding=", 11))
+			metainfo_charset = argv[1] + 11;
+		else
+			usage(mailinfo_usage);
+		argc--; argv++;
+	}
+
+	if (argc != 3)
+		usage(mailinfo_usage);
+
+	return !!mailinfo(stdin, stdout, keep_subject, metainfo_charset, argv[1], argv[2]);
+}