Merge pull request RustPython#670 from coolreader18/pyvaluepayload

Add PyObjectPayload trait and use it for PyObject.payload

Author: coolreader18

vm/src/frame.rs

@@ -76,12 +76,19 @@ impl<'a, T> Iterator for Iter<'a, T> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct Scope {
     locals: RcList<PyObjectRef>,
     pub globals: PyObjectRef,
 }
 
+impl fmt::Debug for Scope {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: have a more informative Debug impl that DOESN'T recurse and cause a stack overflow
+        f.write_str("Scope")
+    }
+}
+
 impl Scope {
     pub fn new(locals: Option<PyObjectRef>, globals: PyObjectRef) -> Scope {
         let locals = match locals {
@@ -99,10 +106,7 @@ impl Scope {
     }
 
     pub fn get_only_locals(&self) -> Option<PyObjectRef> {
-        match self.locals.iter().next() {
-            Some(dict) => Some(dict.clone()),
-            None => None,
-        }
+        self.locals.iter().next().cloned()
     }
 
     pub fn child_scope_with_locals(&self, locals: PyObjectRef) -> Scope {
@@ -1211,22 +1215,25 @@ impl fmt::Debug for Frame {
             .stack
             .borrow()
             .iter()
-            .map(|elem| format!("\n  > {:?}", elem))
-            .collect::<Vec<_>>()
-            .join("");
+            .map(|elem| {
+                if elem.payload.as_any().is::<Frame>() {
+                    "\n  > {frame}".to_string()
+                } else {
+                    format!("\n  > {:?}", elem)
+                }
+            })
+            .collect::<String>();
         let block_str = self
             .blocks
             .borrow()
             .iter()
             .map(|elem| format!("\n  > {:?}", elem))
-            .collect::<Vec<_>>()
-            .join("");
+            .collect::<String>();
         let local_str = match self.scope.get_locals().payload::<PyDict>() {
             Some(dict) => objdict::get_key_value_pairs_from_content(&dict.entries.borrow())
                 .iter()
                 .map(|elem| format!("\n  {:?} = {:?}", elem.0, elem.1))
-                .collect::<Vec<_>>()
-                .join(""),
+                .collect::<String>(),
             None => panic!("locals unexpectedly not wrapping a dict!",),
         };
         write!(

vm/src/obj/objdict.rs

@@ -1,5 +1,6 @@
 use std::cell::{Cell, RefCell};
 use std::collections::HashMap;
+use std::fmt;
 use std::ops::{Deref, DerefMut};
 
 use crate::pyobject::{
@@ -14,13 +15,20 @@ use super::objtype;
 
 pub type DictContentType = HashMap<String, (PyObjectRef, PyObjectRef)>;
 
-#[derive(Default, Debug)]
+#[derive(Default)]
 pub struct PyDict {
     // TODO: should be private
     pub entries: RefCell<DictContentType>,
 }
 pub type PyDictRef = PyRef<PyDict>;
 
+impl fmt::Debug for PyDict {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: implement more detailed, non-recursive Debug formatter
+        f.write_str("dict")
+    }
+}
+
 impl PyValue for PyDict {
     fn required_type(ctx: &PyContext) -> PyObjectRef {
         ctx.dict_type()

vm/src/obj/objlist.rs

@@ -14,13 +14,21 @@ use crate::pyobject::{
 };
 use crate::vm::{ReprGuard, VirtualMachine};
 use num_traits::ToPrimitive;
+use std::fmt;
 
-#[derive(Debug, Default)]
+#[derive(Default)]
 pub struct PyList {
     // TODO: shouldn't be public
     pub elements: RefCell<Vec<PyObjectRef>>,
 }
 
+impl fmt::Debug for PyList {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: implement more detailed, non-recursive Debug formatter
+        f.write_str("list")
+    }
+}
+
 impl From<Vec<PyObjectRef>> for PyList {
     fn from(elements: Vec<PyObjectRef>) -> Self {
         PyList {

vm/src/obj/objobject.rs

@@ -4,13 +4,19 @@ use super::objtype;
 use crate::obj::objproperty::PropertyBuilder;
 use crate::pyobject::{
     AttributeProtocol, DictProtocol, IdProtocol, PyAttributes, PyContext, PyFuncArgs, PyObjectRef,
-    PyRef, PyResult, TypeProtocol,
+    PyRef, PyResult, PyValue, TypeProtocol,
 };
 use crate::vm::VirtualMachine;
 
 #[derive(Clone, Debug)]
 pub struct PyInstance;
 
+impl PyValue for PyInstance {
+    fn required_type(ctx: &PyContext) -> PyObjectRef {
+        ctx.object()
+    }
+}
+
 pub type PyInstanceRef = PyRef<PyInstance>;
 
 pub fn new_instance(vm: &mut VirtualMachine, mut args: PyFuncArgs) -> PyResult {

vm/src/obj/objset.rs

@@ -3,8 +3,8 @@
  */
 
 use std::cell::{Cell, RefCell};
-use std::collections::hash_map::DefaultHasher;
-use std::collections::HashMap;
+use std::collections::{hash_map::DefaultHasher, HashMap};
+use std::fmt;
 use std::hash::{Hash, Hasher};
 
 use super::objbool;
@@ -17,11 +17,18 @@ use crate::pyobject::{
 };
 use crate::vm::{ReprGuard, VirtualMachine};
 
-#[derive(Debug, Default)]
+#[derive(Default)]
 pub struct PySet {
     elements: RefCell<HashMap<u64, PyObjectRef>>,
 }
 
+impl fmt::Debug for PySet {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: implement more detailed, non-recursive Debug formatter
+        f.write_str("set")
+    }
+}
+
 impl PyValue for PySet {
     fn required_type(ctx: &PyContext) -> PyObjectRef {
         ctx.set_type()

vm/src/obj/objtuple.rs

@@ -1,4 +1,5 @@
 use std::cell::{Cell, RefCell};
+use std::fmt;
 use std::hash::{Hash, Hasher};
 
 use crate::pyobject::{
@@ -15,13 +16,20 @@ use super::objsequence::{
 use super::objstr;
 use super::objtype;
 
-#[derive(Debug, Default)]
+#[derive(Default)]
 pub struct PyTuple {
     // TODO: shouldn't be public
     // TODO: tuples are immutable, remove this RefCell
     pub elements: RefCell<Vec<PyObjectRef>>,
 }
 
+impl fmt::Debug for PyTuple {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // TODO: implement more informational, non-recursive Debug formatter
+        f.write_str("tuple")
+    }
+}
+
 impl From<Vec<PyObjectRef>> for PyTuple {
     fn from(elements: Vec<PyObjectRef>) -> Self {
         PyTuple {

vm/src/pyobject.rs

@@ -623,11 +623,7 @@ impl PyContext {
     }
 
     pub fn new_instance(&self, class: PyObjectRef, dict: Option<PyAttributes>) -> PyObjectRef {
-        let dict = if let Some(dict) = dict {
-            dict
-        } else {
-            PyAttributes::new()
-        };
+        let dict = dict.unwrap_or_default();
         PyObject {
             typ: class,
             dict: Some(RefCell::new(dict)),
@@ -697,7 +693,7 @@ impl Default for PyContext {
 pub struct PyObject {
     pub typ: PyObjectRef,
     pub dict: Option<RefCell<PyAttributes>>, // __dict__ member
-    pub payload: Box<dyn Any>,
+    pub payload: Box<dyn PyObjectPayload>,
 }
 
 /// A reference to a Python object.
@@ -1557,7 +1553,7 @@ impl PyValue for PyIteratorValue {
 }
 
 impl PyObject {
-    pub fn new<T: PyValue>(payload: T, typ: PyObjectRef) -> PyObjectRef {
+    pub fn new<T: PyObjectPayload>(payload: T, typ: PyObjectRef) -> PyObjectRef {
         PyObject {
             typ,
             dict: Some(RefCell::new(PyAttributes::new())),
@@ -1571,14 +1567,13 @@ impl PyObject {
         Rc::new(self)
     }
 
+    #[inline]
     pub fn payload<T: PyValue>(&self) -> Option<&T> {
-        self.payload.downcast_ref()
+        self.payload.as_any().downcast_ref()
     }
 }
 
-// The intention is for this to replace `PyObjectPayload` once everything is
-// converted to use `PyObjectPayload::AnyRustvalue`.
-pub trait PyValue: Any + fmt::Debug + Sized {
+pub trait PyValue: fmt::Debug + Sized + 'static {
     fn required_type(ctx: &PyContext) -> PyObjectRef;
 
     fn into_ref(self, ctx: &PyContext) -> PyRef<Self> {
@@ -1603,6 +1598,17 @@ pub trait PyValue: Any + fmt::Debug + Sized {
     }
 }
 
+pub trait PyObjectPayload: Any + fmt::Debug + 'static {
+    fn as_any(&self) -> &dyn Any;
+}
+
+impl<T: PyValue + 'static> PyObjectPayload for T {
+    #[inline]
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+}
+
 impl FromPyObjectRef for PyRef<PyClass> {
     fn from_pyobj(obj: &PyObjectRef) -> Self {
         if let Some(_) = obj.payload::<PyClass>() {

vm/src/stdlib/re.rs

@@ -197,15 +197,15 @@ fn match_end(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 /// Retrieve inner rust regex from python object:
 fn get_regex<'a>(obj: &'a PyObjectRef) -> &'a Regex {
     // TODO: Regex shouldn't be stored in payload directly, create newtype wrapper
-    if let Some(regex) = obj.payload.downcast_ref::<Regex>() {
+    if let Some(regex) = obj.payload::<Regex>() {
         return regex;
     }
     panic!("Inner error getting regex {:?}", obj);
 }
 
 /// Retrieve inner rust match from python object:
 fn get_match<'a>(obj: &'a PyObjectRef) -> &'a PyMatch {
-    if let Some(value) = obj.payload.downcast_ref::<PyMatch>() {
+    if let Some(value) = obj.payload::<PyMatch>() {
         return value;
     }
     panic!("Inner error getting match {:?}", obj);

wasm/lib/src/browser_module.rs

@@ -171,7 +171,7 @@ impl PyPromise {
 }
 
 pub fn get_promise_value(obj: &PyObjectRef) -> Promise {
-    if let Some(promise) = obj.payload.downcast_ref::<PyPromise>() {
+    if let Some(promise) = obj.payload::<PyPromise>() {
         return promise.value.clone();
     }
     panic!("Inner error getting promise")