getSource code for PFunction and PMethods

- optimise imports

- add new __truffle_source__ magic attribute to get the source code of a PFunction

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/function/FunctionBuiltins.java

@@ -29,6 +29,7 @@
 import static com.oracle.graal.python.nodes.SpecialAttributeNames.__DEFAULTS__;
 import static com.oracle.graal.python.nodes.SpecialAttributeNames.__KWDEFAULTS__;
 import static com.oracle.graal.python.nodes.SpecialAttributeNames.__NAME__;
+import static com.oracle.graal.python.nodes.SpecialMethodNames.TRUFFLE_SOURCE;
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__REDUCE__;
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__REPR__;
 import static com.oracle.graal.python.runtime.exception.PythonErrorType.TypeError;
@@ -43,6 +44,7 @@
 import com.oracle.graal.python.builtins.objects.PNone;
 import com.oracle.graal.python.builtins.objects.function.FunctionBuiltinsFactory.GetFunctionDefaultsNodeFactory;
 import com.oracle.graal.python.builtins.objects.function.FunctionBuiltinsFactory.GetFunctionKeywordDefaultsNodeFactory;
+import com.oracle.graal.python.builtins.objects.method.PMethod;
 import com.oracle.graal.python.builtins.objects.str.PString;
 import com.oracle.graal.python.builtins.objects.tuple.PTuple;
 import com.oracle.graal.python.nodes.argument.ReadKeywordNode;
@@ -234,4 +236,31 @@ Object doGeneric(@SuppressWarnings("unused") Object obj) {
         }
     }
 
+    @Builtin(name = TRUFFLE_SOURCE, fixedNumOfPositionalArgs = 1, isGetter = true)
+    @GenerateNodeFactory
+    public abstract static class GetFunctionSourceNode extends PythonUnaryBuiltinNode {
+        @Specialization
+        Object doFunction(PFunction function) {
+            String sourceCode = function.getSourceCode();
+            if (sourceCode != null) {
+                return sourceCode;
+            }
+            return PNone.NONE;
+        }
+
+        @Specialization
+        Object doMethod(PMethod function) {
+            String sourceCode = function.getFunction().getSourceCode();
+            if (sourceCode != null) {
+                return sourceCode;
+            }
+            return PNone.NONE;
+        }
+
+        @Fallback
+        Object doGeneric(Object object) {
+            throw raise(TypeError, "getting the source is not supported for '%p'", object);
+        }
+    }
+
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/function/PFunction.java

@@ -38,6 +38,7 @@
 import com.oracle.truffle.api.RootCallTarget;
 import com.oracle.truffle.api.nodes.RootNode;
 import com.oracle.truffle.api.object.DynamicObject;
+import com.oracle.truffle.api.source.SourceSection;
 
 public class PFunction extends PythonObject {
 
@@ -140,4 +141,12 @@ public Object[] getDefaults() {
     public void setDefaults(Object[] defaults) {
         this.defaults = defaults;
     }
+
+    public String getSourceCode() {
+        SourceSection sourceSection = callTarget.getRootNode().getSourceSection();
+        if (sourceSection != null) {
+            return sourceSection.getCharacters().toString();
+        }
+        return null;
+    }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/SpecialMethodNames.java

@@ -161,4 +161,5 @@ public abstract class SpecialMethodNames {
     public static final String DECODE = "decode";
 
     public static final String RICHCMP = "__truffle_richcompare__";
+    public static final String TRUFFLE_SOURCE = "__truffle_source__";
 }