Refactor methods of Managed_Resource (#3460)

Promoted `with`, `take`, `finalize` to be methods of Managed_Resource
rather than static methods always taking `resource`, for consistency
reasons.

This required function dispatch boilerplate, similarly to `Ref`.
In future iterations we will address this boilerplate code.

Related to https://www.pivotaltracker.com/story/show/182212217

CHANGELOG.md

@@ -122,6 +122,8 @@
   module][3457]
 - [Implemented `Table.parse_values`, parsing text columns according to a
   specified type.][3455]
+- [Promote with, take, finalize to be methods of Managed_Resource
+  instance][3460]
 
 [debug-shortcuts]:
   https://github.com/enso-org/enso/blob/develop/app/gui/docs/product/shortcuts.md#debug
@@ -189,6 +191,7 @@
 [3442]: https://github.com/enso-org/enso/pull/3442
 [3457]: https://github.com/enso-org/enso/pull/3457
 [3455]: https://github.com/enso-org/enso/pull/3455
+[3460]: https://github.com/enso-org/enso/pull/3460
 
 #### Enso Compiler
 

distribution/lib/Standard/Base/0.0.0-dev/src/Runtime/Resource.enso

@@ -36,7 +36,6 @@ type Managed_Resource
        function once it is no longer in use.
 
        Arguments:
-       - resource: The resource to be managed automatically.
        - function: The action to be executed on resource to clean it up when
          it is no longer in use.
     register : Any -> (Any -> Nothing) -> Managed_Resource
@@ -46,11 +45,8 @@ type Managed_Resource
 
        Forces finalization of a managed resource using the registered finalizer,
        even if the resource is still reachable.
-
+    finalize : Nothing
-       Arguments:
+    finalize = @Builtin_Method "Managed_Resource.finalize"
-       - resource: The resource that should be finalized.
-    finalize : Managed_Resource -> Nothing
-    finalize resource = @Builtin_Method "Managed_Resource.finalize"
 
     ## ADVANCED
 
@@ -58,20 +54,15 @@ type Managed_Resource
        resource object.
 
        Arguments:
-       - resource: The managed resource on which to run the action.
        - action: The action that will be applied to the resource managed by
          resource.
-    with : Managed_Resource -> (Any -> Any) -> Any
+    with : (Any -> Any) -> Any
-    with resource ~action = @Builtin_Method "Managed_Resource.with"
+    with ~action = @Builtin_Method "Managed_Resource.with"
 
     ## ADVANCED
 
        Takes the value held by the managed resource and unregisters the
        finalization step for this resource, effectively removing it from the
        managed resources system.
-
-       Arguments:
-       - resource: The managed resource from which to acquire the underlying
-         resource.
     take : Managed_Resource -> Any
-    take resource = @Builtin_Method "Managed_Resource.take"
+    take = @Builtin_Method "Managed_Resource.take"

distribution/lib/Standard/Base/0.0.0-dev/src/System/File.enso

@@ -727,7 +727,7 @@ type Output_Stream
                  out_stream.write_bytes "hello".utf_8
                  out_stream.close
     write_bytes : Vector.Vector -> Nothing ! File_Error
-    write_bytes contents = Managed_Resource.with this.stream_resource java_stream->
+    write_bytes contents = this.stream_resource . with java_stream->
         here.handle_java_exceptions this.file <|
             java_stream.write contents.to_array
             java_stream.flush
@@ -752,7 +752,7 @@ type Output_Stream
                  out_stream = file.new_output_stream [Option.Create]
                  out_stream.close
     close : Nothing
-    close = Managed_Resource.finalize this.stream_resource
+    close = this.stream_resource . finalize
 
 ## An input stream, allowing for interactive reading of contents from an open
    file.
@@ -786,7 +786,7 @@ type Input_Stream
                  in_stream.close
                  bytes
     read_all_bytes : Vector.Vector ! File_Error
-    read_all_bytes = Managed_Resource.with this.stream_resource java_stream->
+    read_all_bytes = this.stream_resource . with java_stream->
         here.handle_java_exceptions this.file <|
             Vector.Vector java_stream.readAllBytes
 
@@ -816,7 +816,7 @@ type Input_Stream
                  in_stream.close
                  bytes
     read_n_bytes : Integer -> Vector.Vector ! File_Error
-    read_n_bytes n = Managed_Resource.with this.stream_resource java_stream->
+    read_n_bytes n = this.stream_resource . with java_stream->
         here.handle_java_exceptions this.file <|
             bytes = java_stream.readNBytes n
             Vector.Vector bytes
@@ -841,7 +841,7 @@ type Input_Stream
                  in_stream.close
                  bytes
     read_byte : Integer ! File_Error
-    read_byte = Managed_Resource.with this.stream_resource java_stream->
+    read_byte = this.stream_resource . with java_stream->
         here.handle_java_exceptions this.file <|
             java_stream.read
 
@@ -864,7 +864,7 @@ type Input_Stream
                  in_stream = file.new_input_stream [Option.Read]
                  in_stream.close
     close : Nothing
-    close = Managed_Resource.finalize this.stream_resource
+    close = this.stream_resource . finalize
 
     ## PRIVATE
 
@@ -876,7 +876,7 @@ type Input_Stream
        Useful when integrating with polyglot functions requiring an
        `InputStream` as an argument.
     with_java_stream : (Java_Input_Stream -> Any) -> Any
-    with_java_stream f = Managed_Resource.with this.stream_resource f
+    with_java_stream f = this.stream_resource . with f
 
 
 ## PRIVATE

distribution/lib/Standard/Database/0.0.0-dev/src/Connection/Connection.enso

@@ -54,7 +54,7 @@ type Connection
        The connection is not usable afterwards.
     close : Nothing
     close =
-        Managed_Resource.finalize this.connection_resource
+        this.connection_resource . finalize
 
     ## ADVANCED
 
@@ -109,7 +109,7 @@ type Connection
        information to any thrown SQL errors.
     with_prepared_statement : Text  | Sql.Statement -> (PreparedStatement -> Any) -> Any
     with_prepared_statement query action =
-        prepare template holes = Managed_Resource.with this.connection_resource java_connection->
+        prepare template holes = this.connection_resource . with java_connection->
             stmt = java_connection.prepareStatement template
             Panic.catch Any (here.set_statement_values stmt holes) caught_panic->
                 stmt.close
@@ -182,7 +182,7 @@ type Connection
         db_types = pairs.map p-> p.second.sql_type
         insert_query = this.dialect.generate_sql <| IR.Insert name pairs
         insert_template = insert_query.prepare.first
-        Managed_Resource.with this.connection_resource java_connection->
+        this.connection_resource . with java_connection->
             default_autocommit = java_connection.getAutoCommit
             java_connection.setAutoCommit False
             Resource.bracket Nothing (_ -> java_connection.setAutoCommit default_autocommit) _->

docs/semantics/managed-resources.md

@@ -51,8 +51,8 @@ call.
 > `Managed_Resource.register` call.
 
 To perform operations on the underlying resource, use the
-`Managed_Resource.with resource action` method, where `resource` is the object
+`<managed-resource>.with action` method, where `<managed-resource>` is the
-returned from the call to `Managed_Resource.register`, and `action` is a
+object returned from the call to `Managed_Resource.register`, and `action` is a
 function taking the underlying object as its only argument. It is important that
 the object passed to `action` is not stored and is not used past the return of
 `action`. This means in particular that it is unsafe to give another thread a
@@ -60,9 +60,8 @@ reference to that object, if the thread remains alive past the return of
 `action`. If such an operation is necessary, the other thread should call `with`
 itself, using a reference to the original manged resource.
 
-A managed resource can be closed manually, using
+A managed resource can be closed manually, using `<managed-resource>.close`. The
-`Managed_Resource.close resource`. The underlying object is then finalized
+underlying object is then finalized immediately.
-immediately.
 
 The finalization of a resource can be aborted using
 `Managed_Resource.take resource`. This call will abort any automatic

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/resource/FinalizeNode.java

@@ -16,12 +16,12 @@ public abstract class FinalizeNode extends Node {
     return FinalizeNodeGen.create();
   }
 
-  abstract Object execute(Object _this, ManagedResource resource);
+  abstract Object execute(Object _this);
 
   @Specialization
-  Object doClose(Object _this, ManagedResource resource) {
+  Object doClose(ManagedResource _this) {
     Context context = Context.get(this);
-    context.getResourceManager().close(resource);
+    context.getResourceManager().close(_this);
     return context.getBuiltins().nothing().newInstance();
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/resource/TakeNode.java

@@ -18,11 +18,11 @@ public abstract class TakeNode extends Node {
     return TakeNodeGen.create();
   }
 
-  abstract Object execute(Object _this, ManagedResource resource);
+  abstract Object execute(Object _this);
 
   @Specialization
-  Object doTake(Object _this, ManagedResource resource) {
+  Object doTake(ManagedResource _this) {
-    Context.get(this).getResourceManager().take(resource);
+    Context.get(this).getResourceManager().take(_this);
-    return resource.getResource();
+    return _this.getResource();
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/resource/WithNode.java

@@ -30,22 +30,16 @@ public abstract class WithNode extends Node {
   }
 
   abstract Stateful execute(
-      @MonadicState Object state,
+      @MonadicState Object state, VirtualFrame frame, Object _this, Object action);
-      VirtualFrame frame,
-      Object _this,
-      ManagedResource resource,
-      Object action);
 
   @Specialization
-  Stateful doWith(
+  Stateful doWith(Object state, VirtualFrame frame, ManagedResource _this, Object action) {
-      Object state, VirtualFrame frame, Object _this, ManagedResource resource, Object action) {
     ResourceManager resourceManager = Context.get(this).getResourceManager();
-    resourceManager.park(resource);
+    resourceManager.park(_this);
     try {
-      return invokeCallableNode.execute(
+      return invokeCallableNode.execute(action, frame, state, new Object[] {_this.getResource()});
-          action, frame, state, new Object[] {resource.getResource()});
     } finally {
-      resourceManager.unpark(resource);
+      resourceManager.unpark(_this);
     }
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/ManagedResource.java

@@ -1,10 +1,20 @@
 package org.enso.interpreter.runtime.data;
 
+import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+import org.enso.interpreter.runtime.Context;
+import org.enso.interpreter.runtime.callable.UnresolvedSymbol;
+import org.enso.interpreter.runtime.callable.function.Function;
+import org.enso.interpreter.runtime.library.dispatch.MethodDispatchLibrary;
 
 import java.lang.ref.PhantomReference;
 
 /** A runtime representation of a managed resource. */
+@ExportLibrary(MethodDispatchLibrary.class)
 public class ManagedResource implements TruffleObject {
   private final Object resource;
   private PhantomReference<ManagedResource> phantomReference;
@@ -37,4 +47,51 @@ public class ManagedResource implements TruffleObject {
   public void setPhantomReference(PhantomReference<ManagedResource> phantomReference) {
     this.phantomReference = phantomReference;
   }
+
+  @ExportMessage
+  boolean hasFunctionalDispatch() {
+    return true;
+  }
+
+  @ExportMessage
+  static class GetFunctionalDispatch {
+
+    static final int CACHE_SIZE = 10;
+
+    @CompilerDirectives.TruffleBoundary
+    static Function doResolve(UnresolvedSymbol symbol) {
+      Context context = getContext();
+      return symbol.resolveFor(
+          context.getBuiltins().managedResource(), context.getBuiltins().any());
+    }
+
+    static Context getContext() {
+      return Context.get(null);
+    }
+
+    @Specialization(
+        guards = {
+          "!getContext().isInlineCachingDisabled()",
+          "cachedSymbol == symbol",
+          "function != null"
+        },
+        limit = "CACHE_SIZE")
+    static Function resolveCached(
+        ManagedResource _this,
+        UnresolvedSymbol symbol,
+        @Cached("symbol") UnresolvedSymbol cachedSymbol,
+        @Cached("doResolve(cachedSymbol)") Function function) {
+      return function;
+    }
+
+    @Specialization(replaces = "resolveCached")
+    static Function resolve(ManagedResource _this, UnresolvedSymbol symbol)
+        throws MethodDispatchLibrary.NoSuchMethodException {
+      Function function = doResolve(symbol);
+      if (function == null) {
+        throw new MethodDispatchLibrary.NoSuchMethodException();
+      }
+      return function;
+    }
+  }
 }

engine/runtime/src/test/scala/org/enso/interpreter/test/semantic/RuntimeManagementTest.scala

@@ -87,7 +87,7 @@ class RuntimeManagementTest extends InterpreterTest {
           |create_resource i =
           |    c = Mock_File i
           |    r = Managed_Resource.register c here.free_resource
-          |    Managed_Resource.with r f-> IO.println ("Accessing: " + f.to_text)
+          |    r . with f-> IO.println ("Accessing: " + f.to_text)
           |
           |main =
           |    here.create_resource 0
@@ -127,8 +127,8 @@ class RuntimeManagementTest extends InterpreterTest {
           |create_resource i =
           |    c = Mock_File i
           |    r = Managed_Resource.register c here.free_resource
-          |    Managed_Resource.with r f-> IO.println ("Accessing: " + f.to_text)
+          |    r . with f-> IO.println ("Accessing: " + f.to_text)
-          |    if i % 2 == 0 then Managed_Resource.finalize r else Nothing
+          |    if i % 2 == 0 then r.finalize else Nothing
           |
           |main =
           |    here.create_resource 0
@@ -168,8 +168,8 @@ class RuntimeManagementTest extends InterpreterTest {
           |create_resource i =
           |    c = Mock_File i
           |    r = Managed_Resource.register c here.free_resource
-          |    Managed_Resource.with r f-> IO.println ("Accessing: " + f.to_text)
+          |    r . with f-> IO.println ("Accessing: " + f.to_text)
-          |    if i % 2 == 0 then Managed_Resource.take r else Nothing
+          |    if i % 2 == 0 then r.take else Nothing
           |
           |main =
           |    here.create_resource 0