Robust against complex text-nodes contains comments, PIs, etc.

[irspy-moved-to-github.git] / lib / ZOOM / IRSpy / Utils.pm

diff --git a/lib/ZOOM/IRSpy/Utils.pm b/lib/ZOOM/IRSpy/Utils.pm
index 008c49a..e52747f 100644 (file)
--- a/lib/ZOOM/IRSpy/Utils.pm
+++ b/lib/ZOOM/IRSpy/Utils.pm
@@ -1,4 +1,4 @@
-# $Id: Utils.pm,v 1.3 2006-10-31 09:26:11 mike Exp $
+# $Id: Utils.pm,v 1.5 2006-11-01 11:46:10 mike Exp $
 
 package ZOOM::IRSpy::Utils;
 
@@ -9,9 +9,14 @@ use warnings;
 use Exporter 'import';
 our @EXPORT_OK = qw(xml_encode 
                    irspy_xpath_context
-                   dom_add_element
+                   modify_xml_document
                    inheritance_tree);
 
+use XML::LibXML;
+use XML::LibXML::XPathContext;
+
+our $IRSPY_NS = 'http://indexdata.com/irspy/1.0';
+
 
 # Utility functions follow, exported for use of web UI
 
@@ -40,11 +45,72 @@ sub irspy_xpath_context {
     my $root = $doc->getDocumentElement();
     my $xc = XML::LibXML::XPathContext->new($root);
     $xc->registerNs(e => 'http://explain.z3950.org/dtd/2.0/');
-    $xc->registerNs(i => $ZOOM::IRSpy::irspy_ns);
+    $xc->registerNs(i => $IRSPY_NS);
     return $xc;
 }
 
 
+sub modify_xml_document {
+    my($xc, $fieldsByKey, $data) = @_;
+
+    my $nchanges = 0;
+    foreach my $key (keys %$data) {
+       my $value = $data->{$key};
+       my $ref = $fieldsByKey->{$key} or die "no field '$key'";
+       my($name, $nlines, $caption, $xpath, @addAfter) = @$ref;
+       #print "Considering $key='$value' ($xpath)<br/>\n";
+       my @nodes = $xc->findnodes($xpath);
+       if (@nodes) {
+           warn scalar(@nodes), " nodes match '$xpath'" if @nodes > 1;
+           my $node = $nodes[0];
+
+           if ($node->isa("XML::LibXML::Attr")) {
+               if ($value ne $node->getValue()) {
+                   $node->setValue($value);
+                   $nchanges++;
+                   print "Attr $key: '", $node->getValue(), "' -> '$value' ($xpath)<br/>\n";
+               }
+           } elsif ($node->isa("XML::LibXML::Element")) {
+               # The contents could be any mixture of text and
+               # comments and maybe even other crud such as processing
+               # instructions.  The simplest thing is just to throw it all
+               # away and start again, making a single Text node the
+               # canonical representation.  But before we do that,
+               # we'll check whether the element is already
+               # canonical, to determine whether our change is a
+               # no-op.
+               my $old = "???";
+               my @children = $node->childNodes();
+               if (@children == 1) {
+                   my $child = $node->firstChild();
+                   if (ref $child && ref $child eq "XML::LibXML::Text") {
+                       $old = $child->getData();
+                       next if $value eq $old;
+                   }
+               }
+
+               $node->removeChildNodes();
+               my $child = new XML::LibXML::Text($value);
+               $node->appendChild($child);
+               $nchanges++;
+               print "Elem $key: '$old' -> '$value' ($xpath)<br/>\n";
+           } else {
+               warn "unexpected node type $node";
+           }
+
+       } else {
+           next if !$value; # No need to create a new empty node
+           my($ppath, $element) = $xpath =~ /(.*)\/(.*)/;
+           dom_add_element($xc, $ppath, $element, $value, @addAfter);
+           print "Add $key ($xpath) = '$value'<br/>\n";
+           $nchanges++;
+       }
+    }
+
+    return $nchanges;
+}
+
+
 sub dom_add_element {
     my($xc, $ppath, $element, $value, @addAfter) = @_;