xbps-query(8: added --cat=FILE mode support.

- This mode prints to stdout the matching FILE stored in a binary package.
- ABI break: renamed xbps_get_pkg_plist_from_binpkg() xbps_binpkg_get_plist().
- Added xbps_binpkg_get_file() as a generic way to get pkg file contents.
- Removed useless comments from xbps_api_impl.h.

bin/xbps-query/defs.h

@@ -46,6 +46,7 @@ int	show_pkg_info_from_metadir(struct xbps_handle *, const char *,
 int	show_pkg_files(xbps_dictionary_t);
 int	show_pkg_files_from_metadir(struct xbps_handle *, const char *);
 int	repo_show_pkg_files(struct xbps_handle *, const char *);
+int	repo_cat_file(struct xbps_handle *, const char *, const char *);
 int	repo_show_pkg_info(struct xbps_handle *, const char *, const char *);
 int 	repo_show_pkg_namedesc(struct xbps_handle *, xbps_object_t, void *,
 		bool *);

bin/xbps-query/main.c

@@ -62,6 +62,7 @@ usage(bool fail)
 	    " -o --ownedby FILE        Search for package files by matching STRING or REGEX\n"
 	    " -S --show PKG            Show information for PKG [default mode]\n"
 	    " -s --search PKG          Search for packages by matching PKG, STRING or REGEX\n"
+	    "    --cat=FILE PKG        Print FILE from PKG binpkg to stdout\n"
 	    " -f --files PKG           Show package files for PKG\n"
 	    " -x --deps PKG            Show dependencies for PKG\n"
 	    " -X --revdeps PKG         Show reverse dependencies for PKG\n");
@@ -86,7 +87,6 @@ main(int argc, char **argv)
 		{ "ownedby", required_argument, NULL, 'o' },
 		{ "property", required_argument, NULL, 'p' },
 		{ "repository", optional_argument, NULL, 'R' },
-		{ "regex", no_argument, NULL, 0 },
 		{ "rootdir", required_argument, NULL, 'r' },
 		{ "show", required_argument, NULL, 'S' },
 		{ "search", required_argument, NULL, 's' },
@@ -95,17 +95,19 @@ main(int argc, char **argv)
 		{ "files", required_argument, NULL, 'f' },
 		{ "deps", required_argument, NULL, 'x' },
 		{ "revdeps", required_argument, NULL, 'X' },
+		{ "regex", no_argument, NULL, 0 },
 		{ "fulldeptree", no_argument, NULL, 1 },
+		{ "cat", required_argument, NULL, 2 },
 		{ NULL, 0, NULL, 0 },
 	};
 	struct xbps_handle xh;
-	const char *pkg, *rootdir, *cachedir, *confdir, *props;
+	const char *pkg, *rootdir, *cachedir, *confdir, *props, *catfile;
 	int c, flags, rv;
 	bool list_pkgs, list_repos, orphans, own;
 	bool list_manual, list_hold, show_prop, show_files, show_deps, show_rdeps;
 	bool show, pkg_search, regex, repo_mode, opmode, fulldeptree;
 
-	rootdir = cachedir = confdir = props = pkg = NULL;
+	rootdir = cachedir = confdir = props = pkg = catfile = NULL;
 	flags = rv = c = 0;
 	list_pkgs = list_repos = list_hold = orphans = pkg_search = own = false;
 	list_manual = show_prop = show_files = false;
@@ -195,6 +197,9 @@ main(int argc, char **argv)
 		case 1:
 			fulldeptree = true;
 			break;
+		case 2:
+			catfile = optarg;
+			break;
 		case '?':
 			usage(true);
 			/* NOTREACHED */
@@ -256,6 +261,10 @@ main(int argc, char **argv)
 		/* search mode */
 		rv = search(&xh, repo_mode, pkg, props, regex);
 
+	} else if (catfile) {
+		/* repo cat file mode */
+		rv =  repo_cat_file(&xh, pkg, catfile);
+
 	} else if (show || show_prop) {
 		/* show mode */
 		if (repo_mode)

bin/xbps-query/ownedby.c

@@ -136,7 +136,7 @@ repo_match_cb(struct xbps_handle *xhp,
 
 	bfile = xbps_repository_pkg_path(xhp, obj);
 	assert(bfile);
-	filesd = xbps_get_pkg_plist_from_binpkg(bfile, "./files.plist");
+	filesd = xbps_binpkg_get_plist(bfile, "/files.plist");
 	if (filesd == NULL) {
 		xbps_dbg_printf(xhp, "%s: couldn't fetch files.plist from %s: %s\n",
 		    pkgver, bfile, strerror(errno));

bin/xbps-query/show-info-files.c

@@ -307,6 +307,31 @@ repo_show_pkg_info(struct xbps_handle *xhp,
 	return 0;
 }
 
+int
+repo_cat_file(struct xbps_handle *xhp, const char *pkg, const char *file)
+{
+	xbps_dictionary_t pkgd;
+	char *url, *buf;
+
+	pkgd = xbps_rpool_get_pkg(xhp, pkg);
+	if (pkgd == NULL)
+		return errno;
+
+	url = xbps_repository_pkg_path(xhp, pkgd);
+	if (url == NULL)
+		return EINVAL;
+
+	xbps_dbg_printf(xhp, "matched pkg at %s\n", url);
+	buf = xbps_binpkg_get_file(url, file);
+	free(url);
+	if (buf == NULL)
+		return ENOENT;
+
+	printf("%s", buf);
+	free(buf);
+	return 0;
+}
+
 int
 repo_show_pkg_files(struct xbps_handle *xhp, const char *pkg)
 {

bin/xbps-query/xbps-query.8

@@ -1,4 +1,4 @@
-.Dd November 5, 2014
+.Dd November 17, 2014
 .Dt XBPS-QUERY 8
 .Sh NAME
 .Nm xbps-query
@@ -211,6 +211,12 @@ If the
 option is set, the matched
 .Ar PKG
 in repositories will be shown.
+.It Fl -repository Fl -cat Ar FILE Ar PKG
+Prints the file
+.Ar FILE
+stored in binary package
+.Ar PKG
+to stdout. This expects an absolute path.
 .El
 .Sh ENVIRONMENT
 .Bl -tag -width XBPS_TARGET_ARCH