From 3b6121f69b2a27c3bbff5cc3056c30b15394441b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20Sandstr=C3=B6m?= <lukass@etek.chalmers.se>
Date: Sun, 13 Jul 2008 20:30:12 +0200
Subject: [PATCH] git-mailinfo: use strbuf's instead of fixed buffers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Lukas Sandström <lukass@etek.chalmers.se>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin-mailinfo.c | 757 +++++++++++++++++++++------------------------
 1 file changed, 352 insertions(+), 405 deletions(-)

diff --git a/builtin-mailinfo.c b/builtin-mailinfo.c
index fa6e8f90a4..3e5fe51085 100644
--- a/builtin-mailinfo.c
+++ b/builtin-mailinfo.c
@@ -5,14 +5,15 @@
 #include "cache.h"
 #include "builtin.h"
 #include "utf8.h"
+#include "strbuf.h"
 
 static FILE *cmitmsg, *patchfile, *fin, *fout;
 
 static int keep_subject;
 static const char *metainfo_charset;
-static char line[1000];
-static char name[1000];
-static char email[1000];
+static struct strbuf line = STRBUF_INIT;
+static struct strbuf name = STRBUF_INIT;
+static struct strbuf email = STRBUF_INIT;
 
 static enum  {
 	TE_DONTCARE, TE_QP, TE_BASE64,
@@ -21,74 +22,79 @@ static enum  {
 	TYPE_TEXT, TYPE_OTHER,
 } message_type;
 
-static char charset[256];
+static struct strbuf charset = STRBUF_INIT;
 static int patch_lines;
-static char **p_hdr_data, **s_hdr_data;
+static struct strbuf **p_hdr_data, **s_hdr_data;
 
 #define MAX_HDR_PARSED 10
 #define MAX_BOUNDARIES 5
 
-static char *sanity_check(char *name, char *email)
+static void get_sane_name(struct strbuf *out, struct strbuf *name, struct strbuf *email)
 {
-	int len = strlen(name);
-	if (len < 3 || len > 60)
-		return email;
-	if (strchr(name, '@') || strchr(name, '<') || strchr(name, '>'))
-		return email;
-	return name;
+	struct strbuf *src = name;
+	if (name->len < 3 || 60 < name->len || strchr(name->buf, '@') ||
+		strchr(name->buf, '<') || strchr(name->buf, '>'))
+		src = email;
+	else if (name == out)
+		return;
+	strbuf_reset(out);
+	strbuf_addbuf(out, src);
 }
 
-static int bogus_from(char *line)
+static void parse_bogus_from(const struct strbuf *line)
 {
 	/* John Doe <johndoe> */
-	char *bra, *ket, *dst, *cp;
 
+	char *bra, *ket;
 	/* This is fallback, so do not bother if we already have an
 	 * e-mail address.
 	 */
-	if (*email)
-		return 0;
+	if (email.len)
+		return;
 
-	bra = strchr(line, '<');
+	bra = strchr(line->buf, '<');
 	if (!bra)
-		return 0;
+		return;
 	ket = strchr(bra, '>');
 	if (!ket)
-		return 0;
+		return;
 
-	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;
+	strbuf_reset(&email);
+	strbuf_add(&email, bra + 1, ket - bra - 1);
+
+	strbuf_reset(&name);
+	strbuf_add(&name, line->buf, bra - line->buf);
+	strbuf_trim(&name);
+	get_sane_name(&name, &name, &email);
 }
 
-static int handle_from(char *in_line)
+static void handle_from(const struct strbuf *from)
 {
-	char line[1000];
 	char *at;
-	char *dst;
+	size_t el;
+	struct strbuf f;
 
-	strcpy(line, in_line);
-	at = strchr(line, '@');
-	if (!at)
-		return bogus_from(line);
+	strbuf_init(&f, from->len);
+	strbuf_addbuf(&f, from);
+
+	at = strchr(f.buf, '@');
+	if (!at) {
+		parse_bogus_from(from);
+		return;
+	}
 
 	/*
 	 * If we already have one email, don't take any confusing lines
 	 */
-	if (*email && strchr(at+1, '@'))
-		return 0;
+	if (email.len && strchr(at + 1, '@')) {
+		strbuf_release(&f);
+		return;
+	}
 
 	/* Pick up the string around '@', possibly delimited with <>
-	 * pair; that is the email part.  White them out while copying.
+	 * pair; that is the email part.
 	 */
-	while (at > line) {
+	while (at > f.buf) {
 		char c = at[-1];
 		if (isspace(c))
 			break;
@@ -98,56 +104,35 @@ static int handle_from(char *in_line)
 		}
 		at--;
 	}
-	dst = email;
-	for (;;) {
-		unsigned char c = *at;
-		if (!c || c == '>' || isspace(c)) {
-			if (c == '>')
-				*at = ' ';
-			break;
-		}
-		*at++ = ' ';
-		*dst++ = c;
-	}
-	*dst++ = 0;
+	el = strcspn(at, " \n\t\r\v\f>");
+	strbuf_reset(&email);
+	strbuf_add(&email, at, el);
+	strbuf_remove(&f, at - f.buf, el + 1);
 
 	/* The remainder is name.  It could be "John Doe <john.doe@xz>"
-	 * or "john.doe@xz (John Doe)", but we have whited out the
+	 * or "john.doe@xz (John Doe)", but we have removed 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;
-		}
-	}
+	strbuf_trim(&f);
+	if (f.buf[0] == '(')
+		strbuf_remove(&name, 0, 1);
+	if (f.len && f.buf[f.len - 1] == ')')
+		strbuf_setlen(&f, f.len - 1);
 
-	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;
+	get_sane_name(&name, &f, &email);
+	strbuf_release(&f);
 }
 
-static int handle_header(char *line, char *data, int ofs)
+static void handle_header(struct strbuf **out, const struct strbuf *line)
 {
-	if (!line || !data)
-		return 1;
+	if (!*out) {
+		*out = xmalloc(sizeof(struct strbuf));
+		strbuf_init(*out, line->len);
+	} else
+		strbuf_reset(*out);
 
-	strcpy(data, line+ofs);
-
-	return 0;
+	strbuf_addbuf(*out, line);
 }
 
 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
@@ -156,13 +141,13 @@ static int handle_header(char *line, char *data, int ofs)
  * case insensitively.
  */
 
-static int slurp_attr(const char *line, const char *name, char *attr)
+static int slurp_attr(const char *line, const char *name, struct strbuf *attr)
 {
 	const char *ends, *ap = strcasestr(line, name);
 	size_t sz;
 
 	if (!ap) {
-		*attr = 0;
+		strbuf_setlen(attr, 0);
 		return 0;
 	}
 	ap += strlen(name);
@@ -173,180 +158,172 @@ static int slurp_attr(const char *line, const char *name, char *attr)
 	else
 		ends = "; \t";
 	sz = strcspn(ap, ends);
-	memcpy(attr, ap, sz);
-	attr[sz] = 0;
+	strbuf_add(attr, ap, sz);
 	return 1;
 }
 
-struct content_type {
-	char *boundary;
-	int boundary_len;
-};
-
-static struct content_type content[MAX_BOUNDARIES];
+static struct strbuf *content[MAX_BOUNDARIES];
 
-static struct content_type *content_top = content;
+static struct strbuf **content_top = content;
 
-static int handle_content_type(char *line)
+static void handle_content_type(struct strbuf *line)
 {
-	char boundary[256];
+	struct strbuf *boundary = xmalloc(sizeof(struct strbuf));
+	strbuf_init(boundary, line->len);
 
-	if (strcasestr(line, "text/") == NULL)
+	if (!strcasestr(line->buf, "text/"))
 		 message_type = TYPE_OTHER;
-	if (slurp_attr(line, "boundary=", boundary + 2)) {
-		memcpy(boundary, "--", 2);
+	if (slurp_attr(line->buf, "boundary=", boundary)) {
+		strbuf_insert(boundary, 0, "--", 2);
 		if (content_top++ >= &content[MAX_BOUNDARIES]) {
 			fprintf(stderr, "Too many boundaries to handle\n");
 			exit(1);
 		}
-		content_top->boundary_len = strlen(boundary);
-		content_top->boundary = xmalloc(content_top->boundary_len+1);
-		strcpy(content_top->boundary, boundary);
+		*content_top = boundary;
+		boundary = NULL;
 	}
-	if (slurp_attr(line, "charset=", charset)) {
-		int i, c;
-		for (i = 0; (c = charset[i]) != 0; i++)
-			charset[i] = tolower(c);
+	if (slurp_attr(line->buf, "charset=", &charset))
+		strbuf_tolower(&charset);
+
+	if (boundary) {
+		strbuf_release(boundary);
+		free(boundary);
 	}
-	return 0;
 }
 
-static int handle_content_transfer_encoding(char *line)
+static void handle_content_transfer_encoding(const struct strbuf *line)
 {
-	if (strcasestr(line, "base64"))
+	if (strcasestr(line->buf, "base64"))
 		transfer_encoding = TE_BASE64;
-	else if (strcasestr(line, "quoted-printable"))
+	else if (strcasestr(line->buf, "quoted-printable"))
 		transfer_encoding = TE_QP;
 	else
 		transfer_encoding = TE_DONTCARE;
-	return 0;
 }
 
-static int is_multipart_boundary(const char *line)
+static int is_multipart_boundary(const struct strbuf *line)
 {
-	return (!memcmp(line, content_top->boundary, content_top->boundary_len));
+	return !strbuf_cmp(line, *content_top);
 }
 
-static int eatspace(char *line)
+static void cleanup_subject(struct strbuf *subject)
 {
-	int len = strlen(line);
-	while (len > 0 && isspace(line[len-1]))
-		line[--len] = 0;
-	return len;
-}
-
-static char *cleanup_subject(char *subject)
-{
-	for (;;) {
-		char *p;
-		int len, remove;
-		switch (*subject) {
+	char *pos;
+	size_t remove;
+	while (subject->len) {
+		switch (*subject->buf) {
 		case 'r': case 'R':
-			if (!memcmp("e:", subject+1, 2)) {
-				subject += 3;
+			if (subject->len <= 3)
+				break;
+			if (!memcmp(subject->buf + 1, "e:", 2)) {
+				strbuf_remove(subject, 0, 3);
 				continue;
 			}
 			break;
 		case ' ': case '\t': case ':':
-			subject++;
+			strbuf_remove(subject, 0, 1);
 			continue;
-
 		case '[':
-			p = strchr(subject, ']');
-			if (!p) {
-				subject++;
-				continue;
-			}
-			len = strlen(p);
-			remove = p - subject;
-			if (remove <= len *2) {
-				subject = p+1;
-				continue;
-			}
+			if ((pos = strchr(subject->buf, ']'))) {
+				remove = pos - subject->buf + 1;
+				/* Don't remove too much. */
+				if (remove <= (subject->len - remove + 1) * 2) {
+					strbuf_remove(subject, 0, remove);
+					continue;
+				}
+			} else
+				strbuf_remove(subject, 0, 1);
 			break;
 		}
-		eatspace(subject);
-		return subject;
+		strbuf_trim(subject);
+		return;
 	}
 }
 
-static void cleanup_space(char *buf)
+static void cleanup_space(struct strbuf *sb)
 {
-	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;
-			}
+	size_t pos, cnt;
+	for (pos = 0; pos < sb->len; pos++) {
+		if (isspace(sb->buf[pos])) {
+			sb->buf[pos] = ' ';
+			for (cnt = 0; isspace(sb->buf[pos + cnt + 1]); cnt++);
+			strbuf_remove(sb, pos + 1, cnt);
 		}
 	}
 }
 
-static void decode_header(char *it, unsigned itsize);
+static void decode_header(struct strbuf *line);
 static const char *header[MAX_HDR_PARSED] = {
 	"From","Subject","Date",
 };
 
-static int check_header(char *line, unsigned linesize, char **hdr_data, int overwrite)
+static inline int cmp_header(const struct strbuf *line, const char *hdr)
 {
-	int i;
+	int len = strlen(hdr);
+	return !strncasecmp(line->buf, hdr, len) && line->len > len &&
+			line->buf[len] == ':' && isspace(line->buf[len + 1]);
+}
 
+static int check_header(const struct strbuf *line,
+				struct strbuf *hdr_data[], int overwrite)
+{
+	int i, ret = 0, len;
+	struct strbuf sb = STRBUF_INIT;
 	/* search for the interesting parts */
 	for (i = 0; header[i]; i++) {
 		int len = strlen(header[i]);
-		if ((!hdr_data[i] || overwrite) &&
-		    !strncasecmp(line, header[i], len) &&
-		    line[len] == ':' && isspace(line[len + 1])) {
+		if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
 			/* Unwrap inline B and Q encoding, and optionally
 			 * normalize the meta information to utf8.
 			 */
-			decode_header(line + len + 2, linesize - len - 2);
-			hdr_data[i] = xmalloc(1000 * sizeof(char));
-			if (! handle_header(line, hdr_data[i], len + 2)) {
-				return 1;
-			}
+			strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
+			decode_header(&sb);
+			handle_header(&hdr_data[i], &sb);
+			ret = 1;
+			goto check_header_out;
 		}
 	}
 
 	/* Content stuff */
-	if (!strncasecmp(line, "Content-Type", 12) &&
-		line[12] == ':' && isspace(line[12 + 1])) {
-		decode_header(line + 12 + 2, linesize - 12 - 2);
-		if (! handle_content_type(line)) {
-			return 1;
-		}
-	}
-	if (!strncasecmp(line, "Content-Transfer-Encoding", 25) &&
-		line[25] == ':' && isspace(line[25 + 1])) {
-		decode_header(line + 25 + 2, linesize - 25 - 2);
-		if (! handle_content_transfer_encoding(line)) {
-			return 1;
-		}
+	if (cmp_header(line, "Content-Type")) {
+		len = strlen("Content-Type: ");
+		strbuf_add(&sb, line->buf + len, line->len - len);
+		decode_header(&sb);
+		strbuf_insert(&sb, 0, "Content-Type: ", len);
+		handle_content_type(&sb);
+		ret = 1;
+		goto check_header_out;
+	}
+	if (cmp_header(line, "Content-Transfer-Encoding")) {
+		len = strlen("Content-Transfer-Encoding: ");
+		strbuf_add(&sb, line->buf + len, line->len - len);
+		decode_header(&sb);
+		handle_content_transfer_encoding(&sb);
+		ret = 1;
+		goto check_header_out;
 	}
 
 	/* for inbody stuff */
-	if (!memcmp(">From", line, 5) && isspace(line[5]))
-		return 1;
-	if (!memcmp("[PATCH]", line, 7) && isspace(line[7])) {
+	if (!prefixcmp(line->buf, ">From") && isspace(line->buf[5])) {
+		ret = 1; /* Should this return 0? */
+		goto check_header_out;
+	}
+	if (!prefixcmp(line->buf, "[PATCH]") && isspace(line->buf[7])) {
 		for (i = 0; header[i]; i++) {
-			if (!memcmp("Subject: ", header[i], 9)) {
-				if (! handle_header(line, hdr_data[i], 0)) {
-					return 1;
-				}
+			if (!memcmp("Subject", header[i], 7)) {
+				handle_header(&hdr_data[i], line);
+				ret = 1;
+				goto check_header_out;
 			}
 		}
 	}
 
-	/* no match */
-	return 0;
+check_header_out:
+	strbuf_release(&sb);
+	return ret;
 }
 
-static int is_rfc2822_header(char *line)
+static int is_rfc2822_header(const struct strbuf *line)
 {
 	/*
 	 * The section that defines the loosest possible
@@ -357,15 +334,15 @@ static int is_rfc2822_header(char *line)
 	 * ftext = %d33-57 / %59-126
 	 */
 	int ch;
-	char *cp = line;
+	char *cp = line->buf;
 
 	/* Count mbox From headers as headers */
-	if (!memcmp(line, "From ", 5) || !memcmp(line, ">From ", 6))
+	if (!prefixcmp(cp, "From ") || !prefixcmp(cp, ">From "))
 		return 1;
 
 	while ((ch = *cp++)) {
 		if (ch == ':')
-			return cp != line;
+			return 1;
 		if ((33 <= ch && ch <= 57) ||
 		    (59 <= ch && ch <= 126))
 			continue;
@@ -374,34 +351,20 @@ static int is_rfc2822_header(char *line)
 	return 0;
 }
 
-/*
- * sz is size of 'line' buffer in bytes.  Must be reasonably
- * long enough to hold one physical real-world e-mail line.
- */
-static int read_one_header_line(char *line, int sz, FILE *in)
+static int read_one_header_line(struct strbuf *line, FILE *in)
 {
-	int len;
-
-	/*
-	 * We will read at most (sz-1) bytes and then potentially
-	 * re-add NUL after it.  Accessing line[sz] after this is safe
-	 * and we can allow len to grow up to and including sz.
-	 */
-	sz--;
-
 	/* Get the first part of the line. */
-	if (!fgets(line, sz, in))
+	if (strbuf_getline(line, in, '\n'))
 		return 0;
 
 	/*
 	 * Is it an empty line or not a valid rfc2822 header?
 	 * If so, stop here, and return false ("not a header")
 	 */
-	len = eatspace(line);
-	if (!len || !is_rfc2822_header(line)) {
+	strbuf_rtrim(line);
+	if (!line->len || !is_rfc2822_header(line)) {
 		/* Re-add the newline */
-		line[len] = '\n';
-		line[len + 1] = '\0';
+		strbuf_addch(line, '\n');
 		return 0;
 	}
 
@@ -410,65 +373,53 @@ static int read_one_header_line(char *line, int sz, FILE *in)
 	 * Yuck, 2822 header "folding"
 	 */
 	for (;;) {
-		int peek, addlen;
-		static char continuation[1000];
+		int peek;
+		struct strbuf continuation = STRBUF_INIT;
 
 		peek = fgetc(in); ungetc(peek, in);
 		if (peek != ' ' && peek != '\t')
 			break;
-		if (!fgets(continuation, sizeof(continuation), in))
+		if (strbuf_getline(&continuation, in, '\n'))
 			break;
-		addlen = eatspace(continuation);
-		if (len < sz - 1) {
-			if (addlen >= sz - len)
-				addlen = sz - len - 1;
-			memcpy(line + len, continuation, addlen);
-			line[len] = '\n';
-			len += addlen;
-		}
+		continuation.buf[0] = '\n';
+		strbuf_rtrim(&continuation);
+		strbuf_addbuf(line, &continuation);
 	}
-	line[len] = 0;
 
 	return 1;
 }
 
-static int decode_q_segment(char *in, char *ot, unsigned otsize, char *ep, int rfc2047)
+static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
 {
-	char *otbegin = ot;
-	char *otend = ot + otsize;
+	const char *in = q_seg->buf;
 	int c;
-	while ((c = *in++) != 0 && (in <= ep)) {
-		if (ot == otend) {
-			*--ot = '\0';
-			return -1;
-		}
+	struct strbuf *out = xmalloc(sizeof(struct strbuf));
+	strbuf_init(out, q_seg->len);
+
+	while ((c = *in++) != 0) {
 		if (c == '=') {
 			int d = *in++;
 			if (d == '\n' || !d)
 				break; /* drop trailing newline */
-			*ot++ = ((hexval(d) << 4) | hexval(*in++));
+			strbuf_addch(out, (hexval(d) << 4) | hexval(*in++));
 			continue;
 		}
 		if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
 			c = 0x20;
-		*ot++ = c;
+		strbuf_addch(out, c);
 	}
-	*ot = 0;
-	return (ot - otbegin);
+	return out;
 }
 
-static int decode_b_segment(char *in, char *ot, unsigned otsize, char *ep)
+static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
 {
 	/* Decode in..ep, possibly in-place to ot */
 	int c, pos = 0, acc = 0;
-	char *otbegin = ot;
-	char *otend = ot + otsize;
+	const char *in = b_seg->buf;
+	struct strbuf *out = xmalloc(sizeof(struct strbuf));
+	strbuf_init(out, b_seg->len);
 
-	while ((c = *in++) != 0 && (in <= ep)) {
-		if (ot == otend) {
-			*--ot = '\0';
-			return -1;
-		}
+	while ((c = *in++) != 0) {
 		if (c == '+')
 			c = 62;
 		else if (c == '/')
@@ -493,21 +444,20 @@ static int decode_b_segment(char *in, char *ot, unsigned otsize, char *ep)
 			acc = (c << 2);
 			break;
 		case 1:
-			*ot++ = (acc | (c >> 4));
+			strbuf_addch(out, (acc | (c >> 4)));
 			acc = (c & 15) << 4;
 			break;
 		case 2:
-			*ot++ = (acc | (c >> 2));
+			strbuf_addch(out, (acc | (c >> 2)));
 			acc = (c & 3) << 6;
 			break;
 		case 3:
-			*ot++ = (acc | c);
+			strbuf_addch(out, (acc | c));
 			acc = pos = 0;
 			break;
 		}
 	}
-	*ot = 0;
-	return (ot - otbegin);
+	return out;
 }
 
 /*
@@ -521,16 +471,16 @@ static int decode_b_segment(char *in, char *ot, unsigned otsize, char *ep)
  * Otherwise, we default to assuming it is Latin1 for historical
  * reasons.
  */
-static const char *guess_charset(const char *line, const char *target_charset)
+static const char *guess_charset(const struct strbuf *line, const char *target_charset)
 {
 	if (is_encoding_utf8(target_charset)) {
-		if (is_utf8(line))
+		if (is_utf8(line->buf))
 			return NULL;
 	}
 	return "latin1";
 }
 
-static void convert_to_utf8(char *line, unsigned linesize, const char *charset)
+static void convert_to_utf8(struct strbuf *line, const char *charset)
 {
 	char *out;
 
@@ -542,112 +492,118 @@ static void convert_to_utf8(char *line, unsigned linesize, const char *charset)
 
 	if (!strcmp(metainfo_charset, charset))
 		return;
-	out = reencode_string(line, metainfo_charset, charset);
+	out = reencode_string(line->buf, metainfo_charset, charset);
 	if (!out)
 		die("cannot convert from %s to %s\n",
 		    charset, metainfo_charset);
-	strlcpy(line, out, linesize);
-	free(out);
+	strbuf_attach(line, out, strlen(out), strlen(out));
 }
 
-static int decode_header_bq(char *it, unsigned itsize)
+static int decode_header_bq(struct strbuf *it)
 {
-	char *in, *out, *ep, *cp, *sp;
-	char outbuf[1000];
+	char *in, *ep, *cp;
+	struct strbuf outbuf = STRBUF_INIT, *dec;
+	struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
 	int rfc2047 = 0;
 
-	in = it;
-	out = outbuf;
-	while ((ep = strstr(in, "=?")) != NULL) {
-		int sz, encoding;
-		char charset_q[256], piecebuf[256];
+	in = it->buf;
+	while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
+		int encoding;
+		strbuf_reset(&charset_q);
+		strbuf_reset(&piecebuf);
 		rfc2047 = 1;
 
 		if (in != ep) {
-			sz = ep - in;
-			memcpy(out, in, sz);
-			out += sz;
-			in += sz;
+			strbuf_add(&outbuf, in, ep - in);
+			in = ep;
 		}
 		/* 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 rfc2047; /* no munging */
-		for (sp = ep; sp < cp; sp++)
-			charset_q[sp - ep] = tolower(*sp);
-		charset_q[cp - ep] = 0;
+
+		if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
+			goto decode_header_bq_out;
+
+		if (cp + 3 - it->buf > it->len)
+			goto decode_header_bq_out;
+		strbuf_add(&charset_q, ep, cp - ep);
+		strbuf_tolower(&charset_q);
+
 		encoding = cp[1];
 		if (!encoding || cp[2] != '?')
-			return rfc2047; /* no munging */
+			goto decode_header_bq_out;
 		ep = strstr(cp + 3, "?=");
 		if (!ep)
-			return rfc2047; /* no munging */
+			goto decode_header_bq_out;
+		strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
 		switch (tolower(encoding)) {
 		default:
-			return rfc2047; /* no munging */
+			goto decode_header_bq_out;
 		case 'b':
-			sz = decode_b_segment(cp + 3, piecebuf, sizeof(piecebuf), ep);
+			dec = decode_b_segment(&piecebuf);
 			break;
 		case 'q':
-			sz = decode_q_segment(cp + 3, piecebuf, sizeof(piecebuf), ep, 1);
+			dec = decode_q_segment(&piecebuf, 1);
 			break;
 		}
-		if (sz < 0)
-			return rfc2047;
 		if (metainfo_charset)
-			convert_to_utf8(piecebuf, sizeof(piecebuf), charset_q);
+			convert_to_utf8(dec, charset_q.buf);
 
-		sz = strlen(piecebuf);
-		if (outbuf + sizeof(outbuf) <= out + sz)
-			return rfc2047; /* no munging */
-		strcpy(out, piecebuf);
-		out += sz;
+		strbuf_addbuf(&outbuf, dec);
+		strbuf_release(dec);
+		free(dec);
 		in = ep + 2;
 	}
-	strcpy(out, in);
-	strlcpy(it, outbuf, itsize);
+	strbuf_addstr(&outbuf, in);
+	strbuf_reset(it);
+	strbuf_addbuf(it, &outbuf);
+decode_header_bq_out:
+	strbuf_release(&outbuf);
+	strbuf_release(&charset_q);
+	strbuf_release(&piecebuf);
 	return rfc2047;
 }
 
-static void decode_header(char *it, unsigned itsize)
+static void decode_header(struct strbuf *it)
 {
-
-	if (decode_header_bq(it, itsize))
+	if (decode_header_bq(it))
 		return;
 	/* otherwise "it" is a straight copy of the input.
 	 * This can be binary guck but there is no charset specified.
 	 */
 	if (metainfo_charset)
-		convert_to_utf8(it, itsize, "");
+		convert_to_utf8(it, "");
 }
 
-static int decode_transfer_encoding(char *line, unsigned linesize, int inputlen)
+static void decode_transfer_encoding(struct strbuf *line)
 {
-	char *ep;
+	struct strbuf *ret;
 
 	switch (transfer_encoding) {
 	case TE_QP:
-		ep = line + inputlen;
-		return decode_q_segment(line, line, linesize, ep, 0);
+		ret = decode_q_segment(line, 0);
+		break;
 	case TE_BASE64:
-		ep = line + inputlen;
-		return decode_b_segment(line, line, linesize, ep);
+		ret = decode_b_segment(line);
+		break;
 	case TE_DONTCARE:
 	default:
-		return inputlen;
+		return;
 	}
+	strbuf_reset(line);
+	strbuf_addbuf(line, ret);
+	strbuf_release(ret);
+	free(ret);
 }
 
-static int handle_filter(char *line, unsigned linesize, int linelen);
+static void handle_filter(struct strbuf *line);
 
 static int find_boundary(void)
 {
-	while(fgets(line, sizeof(line), fin) != NULL) {
-		if (is_multipart_boundary(line))
+	while (!strbuf_getline(&line, fin, '\n')) {
+		if (is_multipart_boundary(&line))
 			return 1;
 	}
 	return 0;
@@ -655,12 +611,17 @@ static int find_boundary(void)
 
 static int handle_boundary(void)
 {
-	char newline[]="\n";
+	struct strbuf newline = STRBUF_INIT;
+
+	strbuf_addch(&newline, '\n');
 again:
-	if (!memcmp(line+content_top->boundary_len, "--", 2)) {
+	if (line.len >= (*content_top)->len + 2 &&
+	    !memcmp(line.buf + (*content_top)->len, "--", 2)) {
 		/* we hit an end boundary */
 		/* pop the current boundary off the stack */
-		free(content_top->boundary);
+		strbuf_release(*content_top);
+		free(*content_top);
+		*content_top = NULL;
 
 		/* technically won't happen as is_multipart_boundary()
 		   will fail first.  But just in case..
@@ -670,7 +631,8 @@ again:
 					"can't recover\n");
 			exit(1);
 		}
-		handle_filter(newline, sizeof(newline), strlen(newline));
+		handle_filter(&newline);
+		strbuf_release(&newline);
 
 		/* skip to the next boundary */
 		if (!find_boundary())
@@ -680,39 +642,44 @@ again:
 
 	/* set some defaults */
 	transfer_encoding = TE_DONTCARE;
-	charset[0] = 0;
+	strbuf_reset(&charset);
 	message_type = TYPE_TEXT;
 
 	/* slurp in this section's info */
-	while (read_one_header_line(line, sizeof(line), fin))
-		check_header(line, sizeof(line), p_hdr_data, 0);
+	while (read_one_header_line(&line, fin))
+		check_header(&line, p_hdr_data, 0);
 
+	strbuf_release(&newline);
 	/* eat the blank line after section info */
-	return (fgets(line, sizeof(line), fin) != NULL);
+	return (strbuf_getline(&line, fin, '\n') == 0);
 }
 
-static inline int patchbreak(const char *line)
+static inline int patchbreak(const struct strbuf *line)
 {
+	size_t i;
+
 	/* Beginning of a "diff -" header? */
-	if (!memcmp("diff -", line, 6))
+	if (!prefixcmp(line->buf, "diff -"))
 		return 1;
 
 	/* CVS "Index: " line? */
-	if (!memcmp("Index: ", line, 7))
+	if (!prefixcmp(line->buf, "Index: "))
 		return 1;
 
 	/*
 	 * "--- <filename>" starts patches without headers
 	 * "---<sp>*" is a manual separator
 	 */
-	if (!memcmp("---", line, 3)) {
-		line += 3;
+	if (line->len < 4)
+		return 0;
+
+	if (!prefixcmp(line->buf, "---")) {
 		/* space followed by a filename? */
-		if (line[0] == ' ' && !isspace(line[1]))
+		if (line->buf[3] == ' ' && !isspace(line->buf[4]))
 			return 1;
 		/* Just whitespace? */
-		for (;;) {
-			unsigned char c = *line++;
+		for (i = 3; i < line->len; i++) {
+			unsigned char c = line->buf[i];
 			if (c == '\n')
 				return 1;
 			if (!isspace(c))
@@ -723,32 +690,24 @@ static inline int patchbreak(const char *line)
 	return 0;
 }
 
-
-static int handle_commit_msg(char *line, unsigned linesize)
+static int handle_commit_msg(struct strbuf *line)
 {
 	static int still_looking = 1;
-	char *endline = line + linesize;
 
 	if (!cmitmsg)
 		return 0;
 
 	if (still_looking) {
-		char *cp = line;
-		if (isspace(*line)) {
-			for (cp = line + 1; *cp; cp++) {
-				if (!isspace(*cp))
-					break;
-			}
-			if (!*cp)
-				return 0;
-		}
-		if ((still_looking = check_header(cp, endline - cp, s_hdr_data, 0)) != 0)
+		strbuf_ltrim(line);
+		if (!line->len)
+			return 0;
+		if ((still_looking = check_header(line, s_hdr_data, 0)) != 0)
 			return 0;
 	}
 
 	/* normalize the log message to UTF-8. */
 	if (metainfo_charset)
-		convert_to_utf8(line, endline - line, charset);
+		convert_to_utf8(line, charset.buf);
 
 	if (patchbreak(line)) {
 		fclose(cmitmsg);
@@ -756,142 +715,132 @@ static int handle_commit_msg(char *line, unsigned linesize)
 		return 1;
 	}
 
-	fputs(line, cmitmsg);
+	fputs(line->buf, cmitmsg);
 	return 0;
 }
 
-static int handle_patch(char *line, int len)
+static void handle_patch(const struct strbuf *line)
 {
-	fwrite(line, 1, len, patchfile);
+	fwrite(line->buf, 1, line->len, patchfile);
 	patch_lines++;
-	return 0;
 }
 
-static int handle_filter(char *line, unsigned linesize, int linelen)
+static void handle_filter(struct strbuf *line)
 {
 	static int filter = 0;
 
-	/* filter tells us which part we left off on
-	 * a non-zero return indicates we hit a filter point
-	 */
+	/* filter tells us which part we left off on */
 	switch (filter) {
 	case 0:
-		if (!handle_commit_msg(line, linesize))
+		if (!handle_commit_msg(line))
 			break;
 		filter++;
 	case 1:
-		if (!handle_patch(line, linelen))
-			break;
-		filter++;
-	default:
-		return 1;
+		handle_patch(line);
+		break;
 	}
-
-	return 0;
 }
 
 static void handle_body(void)
 {
-	int rc = 0;
-	static char newline[2000];
-	static char *np = newline;
-	int len = strlen(line);
+	int len = 0;
+	struct strbuf prev = STRBUF_INIT;
 
 	/* Skip up to the first boundary */
-	if (content_top->boundary) {
+	if (*content_top) {
 		if (!find_boundary())
-			return;
+			goto handle_body_out;
 	}
 
 	do {
+		strbuf_setlen(&line, line.len + len);
+
 		/* process any boundary lines */
-		if (content_top->boundary && is_multipart_boundary(line)) {
+		if (*content_top && is_multipart_boundary(&line)) {
 			/* flush any leftover */
-			if (np != newline)
-				handle_filter(newline, sizeof(newline),
-					      np - newline);
+			if (line.len)
+				handle_filter(&line);
+
 			if (!handle_boundary())
-				return;
-			len = strlen(line);
+				goto handle_body_out;
 		}
 
 		/* Unwrap transfer encoding */
-		len = decode_transfer_encoding(line, sizeof(line), len);
-		if (len < 0) {
-			error("Malformed input line");
-			return;
-		}
+		decode_transfer_encoding(&line);
 
 		switch (transfer_encoding) {
 		case TE_BASE64:
 		case TE_QP:
 		{
-			char *op = line;
+			struct strbuf **lines, **it, *sb;
+
+			/* Prepend any previous partial lines */
+			strbuf_insert(&line, 0, prev.buf, prev.len);
+			strbuf_reset(&prev);
 
 			/* binary data most likely doesn't have newlines */
 			if (message_type != TYPE_TEXT) {
-				rc = handle_filter(line, sizeof(line), len);
+				handle_filter(&line);
 				break;
 			}
-
 			/*
 			 * This is a decoded line that may contain
 			 * multiple new lines.  Pass only one chunk
 			 * at a time to handle_filter()
 			 */
-			do {
-				while (op < line + len && *op != '\n')
-					*np++ = *op++;
-				*np = *op;
-				if (*np != 0) {
-					/* should be sitting on a new line */
-					*(++np) = 0;
-					op++;
-					rc = handle_filter(newline, sizeof(newline), np - newline);
-					np = newline;
-				}
-			} while (op < line + len);
+			lines = strbuf_split(&line, '\n');
+			for (it = lines; (sb = *it); it++) {
+				if (*(it + 1) == NULL) /* The last line */
+					if (sb->buf[sb->len - 1] != '\n') {
+						/* Partial line, save it for later. */
+						strbuf_addbuf(&prev, sb);
+						break;
+					}
+				handle_filter(sb);
+			}
 			/*
-			 * The partial chunk is saved in newline and will be
+			 * The partial chunk is saved in "prev" and will be
 			 * appended by the next iteration of read_line_with_nul().
 			 */
+			strbuf_list_free(lines);
 			break;
 		}
 		default:
-			rc = handle_filter(line, sizeof(line), len);
+			handle_filter(&line);
 		}
-		if (rc)
-			/* nothing left to filter */
-			break;
-	} while ((len = read_line_with_nul(line, sizeof(line), fin)));
 
-	return;
+		strbuf_reset(&line);
+		if (strbuf_avail(&line) < 100)
+			strbuf_grow(&line, 100);
+	} while ((len = read_line_with_nul(line.buf, strbuf_avail(&line), fin)));
+
+handle_body_out:
+	strbuf_release(&prev);
 }
 
-static void output_header_lines(FILE *fout, const char *hdr, char *data)
+static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
 {
+	const char *sp = data->buf;
 	while (1) {
-		char *ep = strchr(data, '\n');
+		char *ep = strchr(sp, '\n');
 		int len;
 		if (!ep)
-			len = strlen(data);
+			len = strlen(sp);
 		else
-			len = ep - data;
-		fprintf(fout, "%s: %.*s\n", hdr, len, data);
+			len = ep - sp;
+		fprintf(fout, "%s: %.*s\n", hdr, len, sp);
 		if (!ep)
 			break;
-		data = ep + 1;
+		sp = ep + 1;
 	}
 }
 
 static void handle_info(void)
 {
-	char *sub;
-	char *hdr;
+	struct strbuf *hdr;
 	int i;
 
 	for (i = 0; header[i]; i++) {
-
 		/* only print inbody headers if we output a patch file */
 		if (patch_lines && s_hdr_data[i])
 			hdr = s_hdr_data[i];
@@ -901,20 +850,18 @@ static void handle_info(void)
 			continue;
 
 		if (!memcmp(header[i], "Subject", 7)) {
-			if (keep_subject)
-				sub = hdr;
-			else {
-				sub = cleanup_subject(hdr);
-				cleanup_space(sub);
+			if (!keep_subject) {
+				cleanup_subject(hdr);
+				cleanup_space(hdr);
 			}
-			output_header_lines(fout, "Subject", sub);
+			output_header_lines(fout, "Subject", hdr);
 		} else if (!memcmp(header[i], "From", 4)) {
 			handle_from(hdr);
-			fprintf(fout, "Author: %s\n", name);
-			fprintf(fout, "Email: %s\n", email);
+			fprintf(fout, "Author: %s\n", name.buf);
+			fprintf(fout, "Email: %s\n", email.buf);
 		} else {
 			cleanup_space(hdr);
-			fprintf(fout, "%s: %s\n", header[i], hdr);
+			fprintf(fout, "%s: %s\n", header[i], hdr->buf);
 		}
 	}
 	fprintf(fout, "\n");
@@ -941,8 +888,8 @@ static int mailinfo(FILE *in, FILE *out, int ks, const char *encoding,
 		return -1;
 	}
 
-	p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(char *));
-	s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(char *));
+	p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*p_hdr_data));
+	s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*s_hdr_data));
 
 	do {
 		peek = fgetc(in);
@@ -950,8 +897,8 @@ static int mailinfo(FILE *in, FILE *out, int ks, const char *encoding,
 	ungetc(peek, in);
 
 	/* process the email header */
-	while (read_one_header_line(line, sizeof(line), fin))
-		check_header(line, sizeof(line), p_hdr_data, 1);
+	while (read_one_header_line(&line, fin))
+		check_header(&line, p_hdr_data, 1);
 
 	handle_body();
 	handle_info();