1 | # $Id: Step.pm 7909 2004-08-06 05:11:55Z mdewsnip $
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2 |
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3 | package XML::XPath::Step;
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4 | use XML::XPath::Parser;
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5 | use XML::XPath::Node;
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6 | use strict;
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7 |
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8 | # the beginnings of using XS for this file...
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9 | # require DynaLoader;
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10 | # use vars qw/$VERSION @ISA/;
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11 | # $VERSION = '1.0';
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12 | # @ISA = qw(DynaLoader);
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13 | #
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14 | # bootstrap XML::XPath::Step $VERSION;
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15 |
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16 | sub test_qname () { 0; } # Full name
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17 | sub test_ncwild () { 1; } # NCName:*
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18 | sub test_any () { 2; } # *
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19 |
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20 | sub test_attr_qname () { 3; } # @ns:attrib
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21 | sub test_attr_ncwild () { 4; } # @nc:*
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22 | sub test_attr_any () { 5; } # @*
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23 |
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24 | sub test_nt_comment () { 6; } # comment()
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25 | sub test_nt_text () { 7; } # text()
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26 | sub test_nt_pi () { 8; } # processing-instruction()
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27 | sub test_nt_node () { 9; } # node()
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28 |
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29 | sub new {
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30 | my $class = shift;
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31 | my ($pp, $axis, $test, $literal) = @_;
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32 | my $axis_method = "axis_$axis";
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33 | $axis_method =~ tr/-/_/;
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34 | my $self = {
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35 | pp => $pp, # the XML::XPath::Parser class
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36 | axis => $axis,
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37 | axis_method => $axis_method,
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38 | test => $test,
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39 | literal => $literal,
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40 | predicates => [],
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41 | };
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42 | bless $self, $class;
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43 | }
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44 |
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45 | sub as_string {
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46 | my $self = shift;
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47 | my $string = $self->{axis} . "::";
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48 |
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49 | my $test = $self->{test};
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50 |
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51 | if ($test == test_nt_pi) {
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52 | $string .= 'processing-instruction(';
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53 | if ($self->{literal}->value) {
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54 | $string .= $self->{literal}->as_string;
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55 | }
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56 | $string .= ")";
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57 | }
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58 | elsif ($test == test_nt_comment) {
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59 | $string .= 'comment()';
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60 | }
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61 | elsif ($test == test_nt_text) {
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62 | $string .= 'text()';
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63 | }
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64 | elsif ($test == test_nt_node) {
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65 | $string .= 'node()';
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66 | }
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67 | elsif ($test == test_ncwild || $test == test_attr_ncwild) {
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68 | $string .= $self->{literal} . ':*';
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69 | }
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70 | else {
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71 | $string .= $self->{literal};
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72 | }
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73 |
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74 | foreach (@{$self->{predicates}}) {
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75 | next unless defined $_;
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76 | $string .= "[" . $_->as_string . "]";
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77 | }
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78 | return $string;
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79 | }
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80 |
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81 | sub as_xml {
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82 | my $self = shift;
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83 | my $string = "<Step>\n";
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84 | $string .= "<Axis>" . $self->{axis} . "</Axis>\n";
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85 | my $test = $self->{test};
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86 |
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87 | $string .= "<Test>";
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88 |
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89 | if ($test == test_nt_pi) {
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90 | $string .= '<processing-instruction';
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91 | if ($self->{literal}->value) {
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92 | $string .= '>';
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93 | $string .= $self->{literal}->as_string;
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94 | $string .= '</processing-instruction>';
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95 | }
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96 | else {
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97 | $string .= '/>';
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98 | }
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99 | }
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100 | elsif ($test == test_nt_comment) {
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101 | $string .= '<comment/>';
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102 | }
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103 | elsif ($test == test_nt_text) {
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104 | $string .= '<text/>';
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105 | }
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106 | elsif ($test == test_nt_node) {
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107 | $string .= '<node/>';
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108 | }
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109 | elsif ($test == test_ncwild || $test == test_attr_ncwild) {
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110 | $string .= '<namespace-prefix>' . $self->{literal} . '</namespace-prefix>';
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111 | }
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112 | else {
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113 | $string .= '<nametest>' . $self->{literal} . '</nametest>';
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114 | }
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115 |
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116 | $string .= "</Test>\n";
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117 |
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118 | foreach (@{$self->{predicates}}) {
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119 | next unless defined $_;
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120 | $string .= "<Predicate>\n" . $_->as_xml() . "</Predicate>\n";
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121 | }
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122 |
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123 | $string .= "</Step>\n";
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124 |
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125 | return $string;
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126 | }
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127 |
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128 | sub evaluate {
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129 | my $self = shift;
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130 | my $from = shift; # context nodeset
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131 |
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132 | # warn "Step::evaluate called with ", $from->size, " length nodeset\n";
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133 |
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134 | $self->{pp}->set_context_set($from);
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135 |
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136 | my $initial_nodeset = XML::XPath::NodeSet->new();
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137 |
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138 | # See spec section 2.1, paragraphs 3,4,5:
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139 | # The node-set selected by the location step is the node-set
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140 | # that results from generating an initial node set from the
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141 | # axis and node-test, and then filtering that node-set by
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142 | # each of the predicates in turn.
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143 |
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144 | # Make each node in the nodeset be the context node, one by one
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145 | for(my $i = 1; $i <= $from->size; $i++) {
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146 | $self->{pp}->set_context_pos($i);
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147 | $initial_nodeset->append($self->evaluate_node($from->get_node($i)));
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148 | }
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149 |
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150 | # warn "Step::evaluate initial nodeset size: ", $initial_nodeset->size, "\n";
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151 |
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152 | $self->{pp}->set_context_set(undef);
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153 |
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154 | $initial_nodeset->sort;
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155 |
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156 | return $initial_nodeset;
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157 | }
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158 |
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159 | # Evaluate the step against a particular node
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160 | sub evaluate_node {
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161 | my $self = shift;
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162 | my $context = shift;
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163 |
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164 | # warn "Evaluate node: $self->{axis}\n";
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165 |
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166 | # warn "Node: ", $context->[node_name], "\n";
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167 |
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168 | my $method = $self->{axis_method};
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169 |
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170 | my $results = XML::XPath::NodeSet->new();
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171 | no strict 'refs';
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172 | eval {
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173 | $method->($self, $context, $results);
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174 | };
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175 | if ($@) {
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176 | die "axis $method not implemented [$@]\n";
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177 | }
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178 |
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179 | # warn("results: ", join('><', map {$_->string_value} @$results), "\n");
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180 | # filter initial nodeset by each predicate
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181 | foreach my $predicate (@{$self->{predicates}}) {
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182 | $results = $self->filter_by_predicate($results, $predicate);
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183 | }
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184 |
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185 | return $results;
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186 | }
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187 |
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188 | sub axis_ancestor {
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189 | my $self = shift;
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190 | my ($context, $results) = @_;
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191 |
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192 | my $parent = $context->getParentNode;
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193 |
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194 | START:
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195 | return $results unless $parent;
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196 | if (node_test($self, $parent)) {
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197 | $results->push($parent);
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198 | }
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199 | $parent = $parent->getParentNode;
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200 | goto START;
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201 | }
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202 |
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203 | sub axis_ancestor_or_self {
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204 | my $self = shift;
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205 | my ($context, $results) = @_;
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206 |
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207 | START:
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208 | return $results unless $context;
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209 | if (node_test($self, $context)) {
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210 | $results->push($context);
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211 | }
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212 | $context = $context->getParentNode;
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213 | goto START;
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214 | }
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215 |
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216 | sub axis_attribute {
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217 | my $self = shift;
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218 | my ($context, $results) = @_;
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219 |
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220 | foreach my $attrib (@{$context->getAttributes}) {
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221 | if ($self->test_attribute($attrib)) {
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222 | $results->push($attrib);
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223 | }
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224 | }
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225 | }
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226 |
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227 | sub axis_child {
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228 | my $self = shift;
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229 | my ($context, $results) = @_;
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230 |
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231 | foreach my $node (@{$context->getChildNodes}) {
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232 | if (node_test($self, $node)) {
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233 | $results->push($node);
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234 | }
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235 | }
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236 | }
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237 |
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238 | sub axis_descendant {
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239 | my $self = shift;
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240 | my ($context, $results) = @_;
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241 |
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242 | my @stack = $context->getChildNodes;
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243 |
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244 | while (@stack) {
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245 | my $node = pop @stack;
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246 | if (node_test($self, $node)) {
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247 | $results->unshift($node);
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248 | }
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249 | push @stack, $node->getChildNodes;
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250 | }
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251 | }
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252 |
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253 | sub axis_descendant_or_self {
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254 | my $self = shift;
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255 | my ($context, $results) = @_;
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256 |
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257 | my @stack = ($context);
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258 |
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259 | while (@stack) {
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260 | my $node = pop @stack;
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261 | if (node_test($self, $node)) {
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262 | $results->unshift($node);
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263 | }
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264 | push @stack, $node->getChildNodes;
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265 | }
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266 | }
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267 |
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268 | sub axis_following {
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269 | my $self = shift;
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270 | my ($context, $results) = @_;
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271 |
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272 | START:
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273 |
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274 | my $parent = $context->getParentNode;
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275 | return $results unless $parent;
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276 |
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277 | while ($context = $context->getNextSibling) {
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278 | axis_descendant_or_self($self, $context, $results);
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279 | }
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280 |
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281 | $context = $parent;
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282 | goto START;
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283 | }
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284 |
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285 | sub axis_following_sibling {
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286 | my $self = shift;
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287 | my ($context, $results) = @_;
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288 |
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289 | while ($context = $context->getNextSibling) {
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290 | if (node_test($self, $context)) {
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291 | $results->push($context);
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292 | }
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293 | }
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294 | }
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295 |
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296 | sub axis_namespace {
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297 | my $self = shift;
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298 | my ($context, $results) = @_;
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299 |
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300 | return $results unless $context->isElementNode;
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301 | foreach my $ns (@{$context->getNamespaces}) {
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302 | if ($self->test_namespace($ns)) {
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303 | $results->push($ns);
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304 | }
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305 | }
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306 | }
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307 |
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308 | sub axis_parent {
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309 | my $self = shift;
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310 | my ($context, $results) = @_;
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311 |
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312 | my $parent = $context->getParentNode;
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313 | return $results unless $parent;
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314 | if (node_test($self, $parent)) {
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315 | $results->push($parent);
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316 | }
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317 | }
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318 |
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319 | sub axis_preceding {
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320 | my $self = shift;
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321 | my ($context, $results) = @_;
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322 |
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323 | # all preceding nodes in document order, except ancestors
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324 |
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325 | START:
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326 |
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327 | my $parent = $context->getParentNode;
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328 | return $results unless $parent;
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329 |
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330 | while ($context = $context->getPreviousSibling) {
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331 | axis_descendant_or_self($self, $context, $results);
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332 | }
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333 |
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334 | $context = $parent;
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335 | goto START;
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336 | }
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337 |
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338 | sub axis_preceding_sibling {
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339 | my $self = shift;
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340 | my ($context, $results) = @_;
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341 |
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342 | while ($context = $context->getPreviousSibling) {
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343 | if (node_test($self, $context)) {
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344 | $results->push($context);
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345 | }
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346 | }
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347 | }
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348 |
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349 | sub axis_self {
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350 | my $self = shift;
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351 | my ($context, $results) = @_;
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352 |
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353 | if (node_test($self, $context)) {
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354 | $results->push($context);
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355 | }
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356 | }
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357 |
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358 | sub node_test {
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359 | my $self = shift;
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360 | my $node = shift;
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361 |
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362 | # if node passes test, return true
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363 |
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364 | my $test = $self->{test};
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365 |
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366 | return 1 if $test == test_nt_node;
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367 |
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368 | if ($test == test_any) {
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369 | return 1 if $node->isElementNode && defined $node->getName;
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370 | }
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371 |
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372 | local $^W;
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373 |
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374 | if ($test == test_ncwild) {
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375 | return unless $node->isElementNode;
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376 | my $match_ns = $self->{pp}->get_namespace($self->{literal}, $node);
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377 | if (my $node_nsnode = $node->getNamespace()) {
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378 | return 1 if $match_ns eq $node_nsnode->getValue;
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379 | }
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380 | }
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381 | elsif ($test == test_qname) {
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382 | return unless $node->isElementNode;
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383 | if ($self->{literal} =~ /:/) {
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384 | my ($prefix, $name) = split(':', $self->{literal}, 2);
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385 | my $match_ns = $self->{pp}->get_namespace($prefix, $node);
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386 | if (my $node_nsnode = $node->getNamespace()) {
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387 | # warn "match: '$self->{literal}' match NS: '$match_ns' got NS: '", $node_nsnode->getValue, "'\n";
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388 | return 1 if ($match_ns eq $node_nsnode->getValue) &&
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389 | ($name eq $node->getLocalName);
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390 | }
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391 | }
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392 | else {
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393 | # warn "Node test: ", $node->getName, "\n";
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394 | return 1 if $node->getName eq $self->{literal};
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395 | }
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396 | }
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397 | elsif ($test == test_nt_text) {
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398 | return 1 if $node->isTextNode;
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399 | }
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400 | elsif ($test == test_nt_comment) {
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401 | return 1 if $node->isCommentNode;
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402 | }
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403 | # elsif ($test == test_nt_pi && !$self->{literal}) {
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404 | # warn "Unreachable code???";
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405 | # return 1 if $node->isPINode;
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406 | # }
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407 | elsif ($test == test_nt_pi) {
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408 | return unless $node->isPINode;
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409 | if (my $val = $self->{literal}->value) {
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410 | return 1 if $node->getTarget eq $val;
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411 | }
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412 | else {
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413 | return 1;
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414 | }
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415 | }
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416 |
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417 | return; # fallthrough returns false
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418 | }
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419 |
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420 | sub test_attribute {
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421 | my $self = shift;
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422 | my $node = shift;
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423 |
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424 | # warn "test_attrib: '$self->{test}' against: ", $node->getName, "\n";
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425 | # warn "node type: $node->[node_type]\n";
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426 |
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427 | my $test = $self->{test};
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428 |
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429 | return 1 if ($test == test_attr_any) || ($test == test_nt_node);
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430 |
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431 | if ($test == test_attr_ncwild) {
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432 | my $match_ns = $self->{pp}->get_namespace($self->{literal}, $node);
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433 | if (my $node_nsnode = $node->getNamespace()) {
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434 | return 1 if $match_ns eq $node_nsnode->getValue;
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435 | }
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436 | }
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437 | elsif ($test == test_attr_qname) {
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438 | if ($self->{literal} =~ /:/) {
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439 | my ($prefix, $name) = split(':', $self->{literal}, 2);
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440 | my $match_ns = $self->{pp}->get_namespace($prefix, $node);
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441 | if (my $node_nsnode = $node->getNamespace()) {
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442 | return 1 if ($match_ns eq $node_nsnode->getValue) &&
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443 | ($name eq $node->getLocalName);
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444 | }
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445 | }
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446 | else {
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447 | return 1 if $node->getName eq $self->{literal};
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448 | }
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449 | }
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450 |
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451 | return; # fallthrough returns false
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452 | }
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453 |
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454 | sub test_namespace {
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455 | my $self = shift;
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456 | my $node = shift;
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457 |
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458 | # Not sure if this is correct. The spec seems very unclear on what
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459 | # constitutes a namespace test... bah!
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460 |
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461 | my $test = $self->{test};
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462 |
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463 | return 1 if $test == test_any; # True for all nodes of principal type
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464 |
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465 | if ($test == test_any) {
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466 | return 1;
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467 | }
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468 | elsif ($self->{literal} eq $node->getExpanded) {
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469 | return 1;
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470 | }
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471 |
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472 | return;
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473 | }
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474 |
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475 | sub filter_by_predicate {
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476 | my $self = shift;
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477 | my ($nodeset, $predicate) = @_;
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478 |
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479 | # See spec section 2.4, paragraphs 2 & 3:
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480 | # For each node in the node-set to be filtered, the predicate Expr
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481 | # is evaluated with that node as the context node, with the number
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482 | # of nodes in the node set as the context size, and with the
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483 | # proximity position of the node in the node set with respect to
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484 | # the axis as the context position.
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485 |
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486 | if (!ref($nodeset)) { # use ref because nodeset has a bool context
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487 | die "No nodeset!!!";
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488 | }
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489 |
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490 | # warn "Filter by predicate: $predicate\n";
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491 |
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492 | my $newset = XML::XPath::NodeSet->new();
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493 |
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494 | for(my $i = 1; $i <= $nodeset->size; $i++) {
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495 | # set context set each time 'cos a loc-path in the expr could change it
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496 | $self->{pp}->set_context_set($nodeset);
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497 | $self->{pp}->set_context_pos($i);
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498 | my $result = $predicate->evaluate($nodeset->get_node($i));
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499 | if ($result->isa('XML::XPath::Boolean')) {
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500 | if ($result->value) {
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501 | $newset->push($nodeset->get_node($i));
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502 | }
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503 | }
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504 | elsif ($result->isa('XML::XPath::Number')) {
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505 | if ($result->value == $i) {
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506 | $newset->push($nodeset->get_node($i));
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507 | }
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508 | }
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509 | else {
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510 | if ($result->to_boolean->value) {
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511 | $newset->push($nodeset->get_node($i));
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512 | }
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513 | }
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514 | }
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515 |
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516 | return $newset;
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517 | }
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518 |
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519 | 1;
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