Jenkins workflow plugin groovy code completion support for IntelliJ IDE

## workflow.gdsl
/*
Author: Gary Clayburg
This file allows IntelliJ IDEA to perform basic syntax checking and code completion for
Jenkins workflow groovy scripts. https://github.com/jenkinsci/workflow-plugin

These methods are supported
sh
readFile
node
echo

Usage:
1. Place this file somewhere in your classpath for the your IntelliJ project
2. You may see a note in IntelliJ IDEA that says "DSL descriptor file has been changed and isn't currently executed."  If you see this, click the "Activate back" button.
3. Your jenkins workflow plugin groovy script should now offer quick Javadoc for supported build steps (sh,readFile,node,echo) and basic autocompletion hints

More background on IntelliJ and groovy DSL support here:
https://confluence.jetbrains.com/display/GRVY/Scripting+IDE+for+DSL+awareness
 */

// Create context for Groovy script files which names end with .groovy
// These definitions allow IntelliJ to autocomplete these variable names injected into groovy scripts/classes.
//def groovyContext = context(filetypes: ['groovy'], scope: scriptScope(name: "flow.groovy")) //restrict these context hints to only files named flow.groovy
def groovyContext = context(filetypes: ['groovy'], scope: scriptScope())

contributor(groovyContext) {
    //injected into all groovy scripts (not necessarily for groovy classes)

    def shDoc = """
Execute a shell script on a Jenkins node
<br/>usage examples:<br/>
<pre>
    sh("ls")
    def tmpdir = "/tmp"
    sh "ls -l \$tmpdir"
    sh 'chmod 755 ./build.sh'
    sh "./build.sh"
    sh script: "ls -l /"
    sh \"\"\" # multiline script
    chmod 644 pom.xml
    ls /
    echo "user home directory is \$HOME"
    \"\"\"

</pre>
"""
    def shParams = [
            parameter(name: 'script', type: String.name, doc: "Bourne shell script text"),
    ]
    method name: "sh", namedParams: shParams, doc: shDoc
    method name: "sh", params: [script: 'java.lang.String'], doc: shDoc

    def echoDoc = """
Print message to Jenkins build log  <br/>
<br/>
Parameters:<br/>
&nbsp&nbsp&nbsp&nbsp<b>message</b>      text of message<br/>
<br/>
<br/>
Usage examples:<br/>
<pre>
    echo 'hello world'
    echo('hi world')
    echo message: \"verbose form of echo\"
</pre>
"""
    def echoParams = [
            parameter(name: 'message', type: String.name, doc: "message text to output to console")
    ]
    method name: 'echo', params: [message: 'java.lang.String'], doc: echoDoc
    method name: 'echo', namedParams: echoParams, doc: echoDoc

    def nodeDoc = """
Allocates an executor on a node (typically a slave) and runs further code in the context of a workspace on that slave. <br/>
<br/>
Usage examples:<br/>
<pre>
node('testingSlaves') {  //testingSlaves must be defined as Jenkins slave label
    // some block
}
</pre>
<pre>
node() {  // execute on any Jenkins slave
    // some block
}
</pre>

"""
    method name: "node", type: "void", params: [label: 'java.lang.String', closure: 'groovy.lang.Closure'], doc: nodeDoc

    method name: "node", type: "void", params: [ closure: 'groovy.lang.Closure'], doc: nodeDoc

    def readFileParams = [
            parameter(name: 'file', type: String.name, doc: "relative or absolute filename of file to read"),
            parameter(name: 'encoding', type: String.name, doc: "character encoding of file (optional)"),
    ]

    def readFileDoc = """
Read a file from workspace with specified encoding  file encoding<br/>
<br/>
Parameters:<br/>
&nbsp&nbsp&nbsp&nbsp<b>file</b>      the path of the file to read<br/>
&nbsp&nbsp&nbsp&nbsp<b>encoding</b>  character encoding of the file.  The platform default is used if this param is not specified<br/>
<br/>
Usage examples:<br/>
<pre>
    def str = readFile file: 'pom.xml', encoding : 'utf-8'  //read utf-8 encoded file
</pre>
<pre>
    def str = readFile file: 'pom.xml'  //read with default encoding
</pre>
<pre>
    def str = readFile 'pom.xml'  //read with default encoding
</pre>

"""
    method name: "readFile", type: "java.lang.String", namedParams: readFileParams, doc: readFileDoc
    method name: "readFile", params: [file: "java.lang.String"], doc: readFileDoc
}

def nodeContext = context(filetypes: ['groovy'], scope: closureScope() )
contributor(nodeContext){
    if (enclosingCall("node")) {  //allows specified methods in node() closure.  This is too restrictive when the node(){} exists in a parent method

//    method name: "sh", params: [scriptText: "java.lang.String"], doc: "run a java shell script"
    }
}