26,12 → 26,57 |
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// $Id$ |
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import java.io.IOException; |
import java.io.LineNumberReader; |
import java.lang.reflect.Field; |
import java.net.URI; |
import java.util.Arrays; |
import java.util.HashMap; |
import java.util.List; |
import java.util.Map; |
import javax.script.Bindings; |
import javax.script.ScriptEngine; |
import javax.script.ScriptEngineManager; |
import javax.script.ScriptException; |
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/** |
* Provides the environment for {@link net.outlyer.plugins.Sandbox}es. |
*/ |
public abstract class PluginEnvironment { |
public class PluginEnvironment { |
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static class UnsupportedAPIException extends PluginException { |
public UnsupportedAPIException(int providedApi) { |
super("Plugin has unsupported API ("+providedApi+")"); |
} |
} |
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static class UnsupportedTypeException extends PluginException { |
public UnsupportedTypeException(String pluginType) { |
super("Plugin has unsupported type ("+pluginType+")"); |
} |
} |
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private final Map<String, Object> exportedObjects; |
private BasePluginObject pluginObject; |
private StringBuilder boilerPlate; |
private List<String> acceptedTypes = null; |
private int maxApi=API.REVISION; |
// Since these lines are evaluated they'll be executed twice |
// so the lower the number the better to reduce unexpected side effects |
private static int linesToCheckForSupport = 1; |
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static final String EXPORTED_SANDBOX_VARIABLE = "$net.outlyer.runtime.sandbox"; |
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{ |
exportedObjects = new HashMap(); |
pluginObject = null; |
boilerPlate = new StringBuilder(); |
} |
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//////////////////////////////////////////////////////// |
// Public interface |
//////////////////////////////////////////////////////// |
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/** |
* Creates a sandbox associated to the script found in uri |
* @param uri Plugin uri |
38,8 → 83,34 |
* @return Sandbox associated to uri |
* @throws net.outlyer.plugins.PluginException |
*/ |
abstract public Sandbox createSandbox(final URI uri) throws PluginException; |
public Sandbox createSandbox(final URI forUri) throws PluginException { |
final ScriptEngine rhino = new ScriptEngineManager().getEngineByName("rhino"); |
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final PluginProperties pp = checkForSupport(forUri); |
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if (null == pluginObject) { |
pluginObject = new PluginObject(); |
} |
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try { |
final PluginObject po = (PluginObject) pluginObject.clone(); |
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final Bindings bindings = rhino.createBindings(); |
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for (final String objectName : exportedObjects.keySet()) { |
bindings.put(objectName, exportedObjects.get(objectName)); |
} |
bindings.put("plugin", po); |
enableSandboxAccess("plugin", po); |
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return new SandboxImpl(forUri, bindings, pp, boilerPlate.toString()); |
} |
catch (final CloneNotSupportedException e) { |
assert false; |
throw new IllegalStateException("Incorrect implementation"); |
} |
} |
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/** |
* Makes an object accessible from the plugin. |
* Note the object will be shared amongst any sandboxes created after |
47,15 → 118,21 |
* @param name Name with which to access the object |
* @param object Object to export |
*/ |
abstract public void exportGlobalObject(final String name, final Object object); |
public void exportGlobalObject(final String name, final Object object) { |
if (null == name) { |
throw new IllegalArgumentException("Can't export an object with" + |
"a null name"); |
} |
if (name.equals("plugin")) { |
throw new IllegalArgumentException("Can't export an object named " + |
"plugin, use setPluginObject() instead"); |
} |
exportedObjects.put(name, object); |
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/** |
* Restricts the set of supported plugins to the ones with the given plugin |
* type (by default no restriction is applied). |
* @see PluginProperties#type |
* @param pluginTypes Set of types to allow; use null to allow all types |
*/ |
abstract public void setAcceptedTypes(final String... pluginTypes); |
if (object instanceof SandboxAccessor) { |
enableSandboxAccess(name, (SandboxAccessor)object); |
} |
} |
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/** |
* Defines the object to be exported as <code>plugin</code>. |
66,9 → 143,147 |
* shared amongst sandboxes, a clone of the one provided will be used. |
* @param pluginObject Object to export, set to null to use a default one. |
*/ |
abstract public void setPluginObject(final BasePluginObject pluginObject); |
public void setPluginObject(BasePluginObject pObject) { |
pluginObject = pObject; |
} |
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public static PluginEnvironment create() { |
return new PluginEnvironmentImpl(); |
/** |
* Restricts the set of supported plugins to the ones with the given plugin |
* type (by default no restriction is applied). |
* @see PluginProperties#type |
* @param pluginTypes Set of types to allow; use null to allow all types |
*/ |
public void setAcceptedTypes(final String ... pluginTypes) { |
if (null != pluginTypes) { |
for (final String type : pluginTypes) { |
if (null == type) { |
throw new IllegalArgumentException("The set of plugin types" + |
" must be either null, or a set of non-null values"); |
} |
} |
} |
acceptedTypes = Arrays.asList(pluginTypes); |
} |
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//////////////////////////////////////////////////////// |
// Non-public interface |
//////////////////////////////////////////////////////// |
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private void enableSandboxAccess(final String name, final SandboxAccessor sa) { |
try { |
Field f = sa.getClass().getField("_getSandbox"); |
} |
catch (final NoSuchFieldException e) { |
throw new IllegalArgumentException("object " + name + " must comply " + |
"with the contract of SandboxAccessor"); |
} |
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final String callback = name + "._getSandbox"; |
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boilerPlate.append(callback).append("=function() {") |
.append(" return ") |
.append(EXPORTED_SANDBOX_VARIABLE).append(";\n};"); |
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} |
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PluginProperties checkForSupport(final URI uri) throws PluginException { |
assert null != uri; |
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final PluginProperties pp = fetchPluginProperties(uri); |
if (null == pp) { |
throw new PluginExecutionException("Failed while inspecting plugin "+uri); |
} |
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if (null != acceptedTypes) { |
if (!acceptedTypes.contains(pp.type)) { |
throw new UnsupportedTypeException(pp.type); |
} |
} |
if (pp.apiVersion > maxApi) { |
throw new UnsupportedAPIException(pp.apiVersion); |
} |
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return pp; |
} |
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// TODO: ? Possibly cache this, so that the first line is only eval'ed |
// once more than the # of executions |
static PluginProperties fetchPluginProperties(final URI uri) { |
assert null != uri; |
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final ScriptEngine rhino = new ScriptEngineManager().getEngineByName("rhino"); |
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try { |
// Define a Plugin object with a field named type |
rhino.eval("var plugin={ type: null, apiVersion: null };"); |
} |
catch (ScriptException e) { |
assert false; |
throw new IllegalStateException("Unknown error encountered"); |
} |
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// First of all check the script for support |
Object type = null, name = null; |
Object apiVersion = null; |
// Try to eval each line, since it executes in a sandbox this is |
// *relatively* safe |
String line; |
try { |
final LineNumberReader script = new LineNumberReader(new PluginReader(uri)); |
try { |
while ((null == type || null == apiVersion || null == name) && |
(null != (line = script.readLine())) && |
script.getLineNumber() <= linesToCheckForSupport) { |
try { |
rhino.eval(line); |
// Note that undefined doesn't convert to null! |
if (null == type) { |
rhino.eval("$_1_$ = (undefined===plugin.type)?null:plugin.type;"); |
type = rhino.get("$_1_$"); |
} |
if (null == apiVersion) { |
rhino.eval("$_1_$ = (undefined===plugin.apiVersion)?null:plugin.apiVersion;"); |
apiVersion = rhino.get("$_1_$"); |
} |
if (null == name) { |
rhino.eval("$_1_$ = (undefined===plugin.name)?null:plugin.name;"); |
name = rhino.get("$_1_$"); |
} |
} |
catch (final ScriptException e) { |
// Exceptions are to be expected since none of the guaranteed |
// plugin tools are provided in this context they'll try to |
// access unexisting objects |
} |
} |
} |
finally { |
script.close(); |
} |
} |
catch (final IOException e) { |
// XXX: Evil silent failure |
return null; |
} |
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if (null == type) { |
type = ""; |
} |
if (null == apiVersion) { |
apiVersion = 0; |
} |
// name can be null |
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final PluginProperties pp = new PluginProperties(); |
try { |
pp.apiVersion = Double.valueOf(apiVersion.toString()).intValue(); |
pp.type = type.toString(); |
pp.name = (null != name) ? name.toString(): null; |
} |
catch (final NumberFormatException e) { |
// XXX: Evil silent failure |
return null; |
} |
return pp; |
} |
} |