Add "whereis" command to xmllint shell

When playing with xpath in the xmllint shell, it's really handy to be
able to ask where the returned nodes live in the tree, in the same
way "pwd" asks where the current node lives.

The feature is actually quite easy to implement by combining the
functionality of the existing dir/ls and pwd commands (see proposed patch).

Example usage:

/ > whereis //last_name
/clinical_study/overall_official/last_name
/clinical_study/location/contact/last_name
/clinical_study/location/investigator/last_name

1 files changed, 78 insertions, 0 deletions

diff --git a/debugXML.c b/debugXML.c
index 30ca6c2a..3e9ec7af 100644
--- a/debugXML.c
+++ b/debugXML.c
@@ -2920,6 +2920,7 @@ xmlShell(xmlDocPtr doc, char *filename, xmlShellReadlineFunc input,
 		  fprintf(ctxt->output, "\t             the default namespace if any uses 'defaultns' prefix\n");
 #endif /* LIBXML_XPATH_ENABLED */
 		  fprintf(ctxt->output, "\tpwd          display current working directory\n");
+		  fprintf(ctxt->output, "\twhereis      display absolute path of [path] or current working directory\n");
 		  fprintf(ctxt->output, "\tquit         leave shell\n");
 #ifdef LIBXML_OUTPUT_ENABLED
 		  fprintf(ctxt->output, "\tsave [name]  save this document to name or the original name\n");
@@ -3159,6 +3160,83 @@ xmlShell(xmlDocPtr doc, char *filename, xmlShellReadlineFunc input,
                 }
                 ctxt->pctxt->node = NULL;
             }
+        } else if (!strcmp(command, "whereis")) {
+            char dir[500];
+
+            if (arg[0] == 0) {
+                if (!xmlShellPwd(ctxt, dir, ctxt->node, NULL))
+                    fprintf(ctxt->output, "%s\n", dir);
+            } else {
+                ctxt->pctxt->node = ctxt->node;
+#ifdef LIBXML_XPATH_ENABLED
+                list = xmlXPathEval((xmlChar *) arg, ctxt->pctxt);
+#else
+                list = NULL;
+#endif /* LIBXML_XPATH_ENABLED */
+                if (list != NULL) {
+                    switch (list->type) {
+                        case XPATH_UNDEFINED:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s: no such node\n", arg);
+                            break;
+                        case XPATH_NODESET:{
+                                int indx;
+
+				if (list->nodesetval == NULL)
+				    break;
+
+                                for (indx = 0;
+                                     indx < list->nodesetval->nodeNr;
+                                     indx++) {
+                                    if (!xmlShellPwd(ctxt, dir, list->nodesetval->
+                                                     nodeTab[indx], NULL))
+                                        fprintf(ctxt->output, "%s\n", dir);
+                                }
+                                break;
+                            }
+                        case XPATH_BOOLEAN:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a Boolean\n", arg);
+                            break;
+                        case XPATH_NUMBER:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a number\n", arg);
+                            break;
+                        case XPATH_STRING:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a string\n", arg);
+                            break;
+                        case XPATH_POINT:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a point\n", arg);
+                            break;
+                        case XPATH_RANGE:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a range\n", arg);
+                            break;
+                        case XPATH_LOCATIONSET:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is a range\n", arg);
+                            break;
+                        case XPATH_USERS:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is user-defined\n", arg);
+                            break;
+                        case XPATH_XSLT_TREE:
+                            xmlGenericError(xmlGenericErrorContext,
+                                            "%s is an XSLT value tree\n",
+                                            arg);
+                            break;
+                    }
+#ifdef LIBXML_XPATH_ENABLED
+                    xmlXPathFreeObject(list);
+#endif
+                } else {
+                    xmlGenericError(xmlGenericErrorContext,
+                                    "%s: no such node\n", arg);
+                }
+                ctxt->pctxt->node = NULL;
+            }
         } else if (!strcmp(command, "cd")) {
             if (arg[0] == 0) {
                 ctxt->node = (xmlNodePtr) ctxt->doc;