Merge pull request #577 from ndw/iss-574

Add p:sleep step

steps/src/main/xml/specification.xml

@@ -236,6 +236,7 @@ PSVI annotations.</para>
 <xi:include href="steps/set-attributes.xml"/>
 <xi:include href="steps/set-properties.xml"/>
 <xi:include href="steps/sink.xml"/>
+<xi:include href="steps/sleep.xml"/>
 <xi:include href="steps/split-sequence.xml"/>
 <xi:include href="steps/store.xml"/>
 <xi:include href="steps/string-replace.xml"/>

steps/src/main/xml/steps/sleep.xml

@@ -0,0 +1,30 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:p="http://www.w3.org/ns/xproc"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="c.sleep">
+<title>p:sleep</title>
+
+<para>The <tag>p:sleep</tag> step introduces a delay.</para>
+
+<p:declare-step type="p:sleep">
+  <p:input port="source" sequence="true" content-types="any"/>
+  <p:output port="result" sequence="true" content-types="any"/>
+  <p:option name="duration" as="xs:nonNegativeInteger" required="true"/>
+</p:declare-step>
+
+<para>The <tag>p:sleep</tag> step copies each of the documents on the
+<port>source</port> port to the <port>result</port> port without changing them.
+Before copying the documents, it pauses for a period of time not less
+than <code>duration</code> milliseconds.</para>
+
+<note>
+<para>In multi-threaded implementations, there is no guarantee that this
+will pause the execution of more than one thread. However, any steps that
+depend on the output of this step will wait for this step to complete.</para>
+</note>
+
+<simplesect>
+<title>Document properties</title>
+<para feature="identity-preserves-all">All document properties are preserved.</para>
+</simplesect>
+</section>