Allow closing config elems with </> if from envvar

The Cyclone DDS configuration is in principle an XML document, but it is
possible to write configuration fragments directly in the CYCLONEDDS_URI
environment variable.  In that case, it is quite annoying to have to
enter the full closing tags all the time, and so it now allows closing
elements with a simple </> when not reading them from a file.

While it would be trivial to also allow this when reading the
configuration from a file, it seems that promulgating invalid XML would
be bad form ... and besides, in that case editors can help keep
everything in order.

Signed-off-by: Erik Boasson <eb@ilities.com>

src/core/ddsi/src/q_config.c

@@ -2685,7 +2685,7 @@ struct cfgst * config_init (const char *configfile)
       if (tok[0] == '<') {
         /* Read XML directly from input string */
         qx = ddsrt_xmlp_new_string (tok, cfgst, &cb);
-        ddsrt_xmlp_set_requireEOF (qx, 0);
+        ddsrt_xmlp_set_options (qx, DDSRT_XMLP_ANONYMOUS_CLOSE_TAG);
         fp = NULL;
       } else {
         char *comma;

src/ddsrt/include/dds/ddsrt/xmlparser.h

@@ -36,9 +36,12 @@ extern "C" {
 
     struct ddsrt_xmlp_state;
 
+#define DDSRT_XMLP_REQUIRE_EOF         1u /* set by default; if not set, junk may follow top-level closing tag */
+#define DDSRT_XMLP_ANONYMOUS_CLOSE_TAG 2u /* clear by default; if set allow closing an element with </> instead of </name> */
+
     DDS_EXPORT struct ddsrt_xmlp_state *ddsrt_xmlp_new_file (FILE *fp, void *varg, const struct ddsrt_xmlp_callbacks *cb);
     DDS_EXPORT struct ddsrt_xmlp_state *ddsrt_xmlp_new_string (const char *string, void *varg, const struct ddsrt_xmlp_callbacks *cb);
-    DDS_EXPORT void ddsrt_xmlp_set_requireEOF (struct ddsrt_xmlp_state *st, int require_eof);
+    DDS_EXPORT void ddsrt_xmlp_set_options (struct ddsrt_xmlp_state *st, unsigned options);
     DDS_EXPORT size_t ddsrt_xmlp_get_bufpos (const struct ddsrt_xmlp_state *st);
     DDS_EXPORT void ddsrt_xmlp_free (struct ddsrt_xmlp_state *st);
     DDS_EXPORT int ddsrt_xmlp_parse (struct ddsrt_xmlp_state *st);

src/ddsrt/src/xmlparser.c

@@ -49,7 +49,7 @@ struct ddsrt_xmlp_state {
     size_t tpescp; /* still escape sequences in tpescp .. tpp */
     int nest; /* current nesting level */
     void *varg; /* user argument to callback functions */
-    int require_eof; /* if false, junk may follow top-level closing tag */
+    unsigned options;
     struct ddsrt_xmlp_callbacks cb; /* user-supplied callbacks (or stubs) */
 };
 
@@ -108,7 +108,7 @@ static void ddsrt_xmlp_new_common (struct ddsrt_xmlp_state *st)
     st->peekpayload = NULL;
     st->nest = 0;
     st->error = 0;
-    st->require_eof = 1;
+    st->options = DDSRT_XMLP_REQUIRE_EOF;
 }
 
 static void ddsrt_xmlp_new_setCB (struct ddsrt_xmlp_state *st, void *varg, const struct ddsrt_xmlp_callbacks *cb)
@@ -148,9 +148,9 @@ struct ddsrt_xmlp_state *ddsrt_xmlp_new_string (const char *string, void *varg,
     return st;
 }
 
-void ddsrt_xmlp_set_requireEOF (struct ddsrt_xmlp_state *st, int require_eof)
+void ddsrt_xmlp_set_options (struct ddsrt_xmlp_state *st, unsigned options)
 {
-    st->require_eof = require_eof;
+    st->options = options;
 }
 
 size_t ddsrt_xmlp_get_bufpos (const struct ddsrt_xmlp_state *st)
@@ -451,12 +451,15 @@ static int next_token_tag_withoutclose (struct ddsrt_xmlp_state *st, char **payl
             next_char (st);
         }
         /* we only do tag names that are identifiers */
-        if (!qq_isidentfirst (peek_char (st))) {
+        if (peek_char (st) == '>' && (st->options & DDSRT_XMLP_ANONYMOUS_CLOSE_TAG)) {
+            return TOK_SHORTHAND_CLOSE_TAG;
+        } else if (!qq_isidentfirst (peek_char (st))) {
             return TOK_ERROR;
-        }
+        } else {
             next_token_ident (st, payload);
             return tok;
         }
+    }
 }
 
 static int next_token_string (struct ddsrt_xmlp_state *st, char **payload)
@@ -560,6 +563,9 @@ static int next_token (struct ddsrt_xmlp_state *st, char **payload)
             }
         }
         if (tok == TOK_ERROR) {
+            char msg[512];
+            (void) snprintf (msg, sizeof (msg), "invalid token encountered");
+            st->cb.error (st->varg, msg, st->line);
             st->error = 1;
         }
         return tok;
@@ -674,10 +680,10 @@ static int parse_element (struct ddsrt_xmlp_state *st, uintptr_t parentinfo)
                 }
             }
             st->nest--;
-            if (next_token (st, &ename) != TOK_CLOSE_TAG || next_char (st) != '>') {
+            if (((tok = next_token (st, &ename)) != TOK_CLOSE_TAG && tok != TOK_SHORTHAND_CLOSE_TAG) || next_char (st) != '>') {
                 PE_LOCAL_ERROR ("expecting closing tag", name);
             }
-            if (strcmp (name, ename) != 0) {
+            if (tok != TOK_SHORTHAND_CLOSE_TAG && strcmp (name, ename) != 0) {
                 PE_LOCAL_ERROR ("open/close tag mismatch", ename);
             }
             ret = st->cb.elem_close (st->varg, eleminfo);
@@ -709,7 +715,7 @@ int ddsrt_xmlp_parse (struct ddsrt_xmlp_state *st)
         return 0;
     } else {
         int ret = parse_element (st, 0);
-        if (ret < 0|| !st->require_eof || next_token (st, NULL) == TOK_EOF ) {
+        if (ret < 0|| !(st->options & DDSRT_XMLP_REQUIRE_EOF) || next_token (st, NULL) == TOK_EOF ) {
             return ret;
         } else {
             return -1;