boardd: article{stat,part,head,tail} keys.

"<bid>.articlestat.<filename>"
  => "<cachekey>,<filesize>"

"<bid>.article<method>.<cachekey>.<offset>.<maxlen>.<filename>"
  => "<metaline>\n<content>"

method = "part" | "head" | "tail"
metaline = "<cachekey>,<filesize>,<offset>,<length>"

Cache key is a key that can be used to check if the file is edit by user.
Currently, "<st_dev>-<st_ino>" is used for approximation.

Each method operates content in file described by <offset> and <length>.
The function of methods is described as below:

part - output the desired part of file.
head - select a good portion from the beginning of the part.
       (eg. end with a new-line; not inside a DBCS char)
tail - select a good portion from the end of the part.

Note that <offset> and <length> correspond to the original file,
not to be confused with conversions. (eg. UTF-8)



git-svn-id: http://opensvn.csie.org/pttbbs/trunk@6077 63ad8ddf-47c3-0310-b6dd-a9e9d9715204

1 files changed, 217 insertions, 6 deletions

diff --git a/pttbbs/daemon/boardd/boardd.c b/pttbbs/daemon/boardd/boardd.c
index fd4200d1..e5273438 100644
--- a/pttbbs/daemon/boardd/boardd.c
+++ b/pttbbs/daemon/boardd/boardd.c
@@ -69,6 +69,199 @@ article_list(struct evbuffer *buf, boardheader_t *bptr, int offset, int length)
 	close(fd);
 }
 
+static int
+is_valid_article_filename(const char *filename)
+{
+    return !strncmp(filename, "M.", 2);
+}
+
+static int
+answer_file(struct evbuffer *buf, const char *path, struct stat *st,
+	    const char *ck, int cklen, int offset, int maxlen)
+{
+    struct stat local_st;
+    int fd;
+
+    if (st == NULL)
+	st = &local_st;
+
+    if ((fd = open(path, O_RDONLY)) < 0 || fstat(fd, st) < 0)
+	goto answer_file_errout;
+
+    if (ck && cklen) {
+	char ckbuf[128];
+	snprintf(ckbuf, sizeof(ckbuf), "%d-%d", st->st_dev, st->st_ino);
+	if (strncmp(ck, ckbuf, cklen) != 0)
+	    goto answer_file_errout;
+    }
+
+    if (offset < 0)
+	offset += st->st_size;
+    if (offset < 0)
+	offset = 0;
+    if (offset > st->st_size)
+	goto answer_file_errout;
+
+    if (maxlen < 0 || offset + maxlen > st->st_size)
+	maxlen = st->st_size - offset;
+
+    if (evbuffer_add_file(buf, fd, offset, maxlen) == 0)
+	return 0;
+
+answer_file_errout:
+    if (fd >= 0)
+	close(fd);
+    return -1;
+}
+
+static int
+parse_articlepart_key(const char *key, const char **ck, int *cklen,
+		      int *offset, int *maxlen, const char **filename)
+{
+    // <key> = <cache_key>.<offset>.<maxlen>.<filename>
+    *ck = key;
+    int i;
+    for (i = 0; key[i]; i++) {
+	if (key[i] == '.') {
+	    *cklen = i;
+	    break;
+	}
+    }
+    if (key[i] != '.')
+	return 0;
+    key += i + 1;
+
+    char *p;
+    *offset = strtol(key, &p, 10);
+    if (*p != '.')
+	return 0;
+    key = p + 1;
+
+    *maxlen = strtol(key, &p, 10);
+    if (*p != '.')
+	return 0;
+
+    *filename = p + 1;
+    return 1;
+}
+
+static int
+find_good_truncate_point_from_begin(const char *content, int size)
+{
+    int last_startline = 0;
+    int last_charend = 0;
+    int last_dbcstail = 0;
+    int i;
+    const char *p;
+    for (i = 1, p = content; i <= size; i++, p++) {
+	if (i > last_dbcstail) {
+	    if (IS_DBCSLEAD(*p)) {
+		last_dbcstail = i + 1;
+		if (i + 1 <= size)
+		    last_charend = i + 1;
+	    } else
+		last_charend = i;
+	}
+	if (*p == '\n')
+	    last_startline = i;
+    }
+    return last_startline > 0 ? last_startline : last_charend;
+}
+
+static int
+find_good_truncate_point_from_end(const char *content, int size)
+{
+    int i;
+    const char *p;
+    for (i = 1, p = content; i <= size; i++, p++)
+	if (*p == '\n')
+	    return i;
+    return 0;
+}
+
+static int
+select_article_head(const char *data, int len, int *offset, int *size, void *ctx)
+{
+    *offset = 0;
+    *size = find_good_truncate_point_from_begin(data, len);
+    return 0;
+}
+
+static int
+select_article_tail(const char *data, int len, int *offset, int *size, void *ctx)
+{
+    *offset = find_good_truncate_point_from_end(data, len);
+    *size = find_good_truncate_point_from_begin(data + *offset, len - *offset);
+    return 0;
+}
+
+static int
+select_article_part(const char *data, int len, int *offset, int *size, void *ctx)
+{
+    *offset = 0;
+    *size = len;
+    return 0;
+}
+
+static void
+cleanup_evbuffer(const void *data, size_t datalen, void *extra)
+{
+    evbuffer_free((struct evbuffer *)extra);
+}
+
+static int
+evbuffer_slice(struct evbuffer *buf, int offset, int size)
+{
+    int len = evbuffer_get_length(buf);
+    if (offset + size > len)
+	return -1;
+
+    struct evbuffer *back = evbuffer_new();
+    evbuffer_add_buffer(back, buf);
+
+    if (evbuffer_add_reference(buf, evbuffer_pullup(back, len) + offset,
+			       size, cleanup_evbuffer, back) == 0)
+	return 0;
+
+    evbuffer_free(back);
+    return -1;
+}
+
+typedef int (*select_part_func)(const char *data, int len, int *offset, int *size, void *ctx);
+
+static int
+answer_articleselect(struct evbuffer *buf, const boardheader_t *bptr,
+		     const char *rest_key, select_part_func sfunc, void *ctx)
+{
+    char path[PATH_MAX];
+    const char *ck, *filename;
+    int cklen, offset, maxlen;
+    struct stat st;
+
+    if (!parse_articlepart_key(rest_key, &ck, &cklen, &offset, &maxlen, &filename))
+	return -1;
+
+    if (!is_valid_article_filename(filename))
+	return -1;
+
+    setbfile(path, bptr->brdname, filename);
+    if (answer_file(buf, path, &st, ck, cklen, offset, maxlen) < 0)
+	return -1;
+
+    int sel_offset, sel_size;
+    int len = evbuffer_get_length(buf);
+    if (sfunc(evbuffer_pullup(buf, len), len, &sel_offset, &sel_size, ctx) != 0 ||
+	evbuffer_slice(buf, sel_offset, sel_size) != 0)
+	return -1;
+
+    struct evbuffer *meta = evbuffer_new();
+    evbuffer_add_printf(meta, "%d-%d,%lu,%d,%d\n",
+			st.st_dev, st.st_ino, st.st_size, sel_offset, sel_size);
+    evbuffer_prepend_buffer(buf, meta);
+    evbuffer_free(meta);
+    return 0;
+}
+
 static void
 answer_key(struct evbuffer *buf, const char *key)
 {
@@ -133,9 +326,9 @@ answer_key(struct evbuffer *buf, const char *key)
 	    if (!p || (length = atoi(p+1)) == 0)
 		length = DEFAULT_ARTICLE_LIST;
 
-	    return article_list(buf, bptr, offset, length);
+	    article_list(buf, bptr, offset, length);
 	} else if (strncmp(key, "article.", 8) == 0) {
-	    if (strncmp(key + 8, "M.", 2) != 0)
+	    if (!is_valid_article_filename(key + 8))
 		return;
 
 	    char path[PATH_MAX];
@@ -145,10 +338,28 @@ answer_key(struct evbuffer *buf, const char *key)
 	    setbfile(path, bptr->brdname, key + 8);
 	    if ((fd = open(path, O_RDONLY)) < 0)
 		return;
-            if (fstat(fd, &st) < 0 ||
-                st.st_size == 0 ||
-                evbuffer_add_file(buf, fd, 0, st.st_size) != 0)
-                close(fd);
+	    if (fstat(fd, &st) < 0 ||
+		st.st_size == 0 ||
+		evbuffer_add_file(buf, fd, 0, st.st_size) != 0)
+		close(fd);
+	} else if (strncmp(key, "articlestat.", 12) == 0) {
+	    if (!is_valid_article_filename(key + 12))
+		return;
+
+	    char path[PATH_MAX];
+	    struct stat st;
+
+	    setbfile(path, bptr->brdname, key + 12);
+	    if (stat(path, &st) < 0)
+		return;
+
+	    evbuffer_add_printf(buf, "%d-%d,%ld", st.st_dev, st.st_ino, st.st_size);
+	} else if (strncmp(key, "articlepart.", 12) == 0) {
+	    answer_articleselect(buf, bptr, key + 12, select_article_part, NULL);
+	} else if (strncmp(key, "articlehead.", 12) == 0) {
+	    answer_articleselect(buf, bptr, key + 12, select_article_head, NULL);
+	} else if (strncmp(key, "articletail.", 12) == 0) {
+	    answer_articleselect(buf, bptr, key + 12, select_article_tail, NULL);
 	} else
 	    return;
     } else if (strncmp(key, "tobid.", 6) == 0) {