Patch #957398: Add public API for Generator Object/Type.

7 files changed, 207 insertions, 138 deletions

diff --git a/Doc/api/concrete.tex b/Doc/api/concrete.tex
index e602528..62084bd 100644
--- a/Doc/api/concrete.tex
+++ b/Doc/api/concrete.tex
@@ -2603,3 +2603,34 @@ when accessed.  Cell objects are not likely to be useful elsewhere.
   reference counts are adjusted, and no checks are made for safety;
   \var{cell} must be non-\NULL{} and must be a cell object.
 \end{cfuncdesc}
+
+
+\subsection{Generator Objects \label{gen-objects}}
+
+Generator objects are what Python uses to implement generator iterators.
+They are normally created by iterating over a function that yields values,
+rather than explicitly calling \cfunction{PyGen_New}.
+
+\begin{ctypedesc}{PyGenObject}
+  The C structure used for generator objects.
+\end{ctypedesc}
+
+\begin{cvardesc}{PyTypeObject}{PyGen_Type}
+  The type object corresponding to generator objects
+\end{cvardesc}
+
+\begin{cfuncdesc}{int}{PyGen_Check}{ob}
+  Return true if \var{ob} is a generator object; \var{ob} must not be
+  \NULL.
+\end{cfuncdesc}
+
+\begin{cfuncdesc}{int}{PyGen_CheckExact}{ob}
+  Return true if \var{ob}'s type is \var{PyGen_Type}
+  is a generator object; \var{ob} must not be
+  \NULL.
+\end{cfuncdesc}
+
+\begin{cfuncdesc}{PyObject*}{PyGen_New}{PyFrameObject *frame}
+  Create and return a new generator object based on the \var{frame} object.
+  The parameter must not be \NULL.
+\end{cfuncdesc}
diff --git a/Include/ceval.h b/Include/ceval.h
index dc3864b..ae6de3a 100644
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -64,6 +64,7 @@ PyAPI_FUNC(char *) PyEval_GetFuncName(PyObject *);
 PyAPI_FUNC(char *) PyEval_GetFuncDesc(PyObject *);
 
 PyAPI_FUNC(PyObject *) PyEval_GetCallStats(PyObject *);
+PyAPI_FUNC(PyObject *) PyEval_EvaluateFrame(PyObject *);
 
 /* this used to be handled on a per-thread basis - now just two globals */
 PyAPI_DATA(volatile int) _Py_Ticker;
diff --git a/Include/genobject.h b/Include/genobject.h
new file mode 100644
index 0000000..c9b7c19
--- /dev/null
+++ b/Include/genobject.h
@@ -0,0 +1,33 @@
+
+/* Generator object interface */
+
+#ifndef Py_GENOBJECT_H
+#define Py_GENOBJECT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+	PyObject_HEAD
+	/* The gi_ prefix is intended to remind of generator-iterator. */
+
+	PyFrameObject *gi_frame;
+
+	/* True if generator is being executed. */
+	int gi_running;
+
+	/* List of weak reference. */
+	PyObject *gi_weakreflist;
+} PyGenObject;
+
+PyAPI_DATA(PyTypeObject) PyGen_Type;
+
+#define PyGen_Check(op) PyObject_TypeCheck(op, &PyGen_Type)
+#define PyGen_CheckExact(op) ((op)->ob_type == &PyGen_Type)
+
+PyAPI_FUNC(PyObject *) PyGen_New(PyFrameObject *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_GENOBJECT_H */
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 9a50039..074fba4 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -261,6 +261,7 @@ OBJECT_OBJS=	\
 		Objects/complexobject.o \
 		Objects/descrobject.o \
 		Objects/enumobject.o \
+		Objects/genobject.o \
 		Objects/fileobject.o \
 		Objects/floatobject.o \
 		Objects/frameobject.o \
@@ -478,6 +479,7 @@ PYTHON_HEADERS= \
 		Include/descrobject.h \
 		Include/dictobject.h \
 		Include/enumobject.h \
+		Include/genobject.h \
 		Include/fileobject.h \
 		Include/floatobject.h \
 		Include/funcobject.h \
diff --git a/Misc/NEWS b/Misc/NEWS
index 2c5dfd9..33bfc43 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -497,6 +497,9 @@ Build
 C API
 -----
 
+- New public functions PyEval_EvaluateFrame and PyGen_New to expose
+  generator objects.
+
 - New public functions Py_IncRef() and Py_DecRef(), exposing the
   functionality of the Py_XINCREF() and Py_XDECREF macros. Useful for
   runtime dynamic embedding of Python.  See patch #938302, by Bob
diff --git a/Objects/genobject.c b/Objects/genobject.c
new file mode 100644
index 0000000..0f7373a
--- /dev/null
+++ b/Objects/genobject.c
@@ -0,0 +1,129 @@
+/* Generator object implementation */
+
+#include "Python.h"
+#include "frameobject.h"
+#include "genobject.h"
+#include "ceval.h"
+#include "structmember.h"
+
+static int
+gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
+{
+	return visit((PyObject *)gen->gi_frame, arg);
+}
+
+static void
+gen_dealloc(PyGenObject *gen)
+{
+	_PyObject_GC_UNTRACK(gen);
+	if (gen->gi_weakreflist != NULL)
+		PyObject_ClearWeakRefs((PyObject *) gen);
+	Py_DECREF(gen->gi_frame);
+	PyObject_GC_Del(gen);
+}
+
+static PyObject *
+gen_iternext(PyGenObject *gen)
+{
+	PyThreadState *tstate = PyThreadState_GET();
+	PyFrameObject *f = gen->gi_frame;
+	PyObject *result;
+
+	if (gen->gi_running) {
+		PyErr_SetString(PyExc_ValueError,
+				"generator already executing");
+		return NULL;
+	}
+	if (f->f_stacktop == NULL)
+		return NULL;
+
+	/* Generators always return to their most recent caller, not
+	 * necessarily their creator. */
+	Py_XINCREF(tstate->frame);
+	assert(f->f_back == NULL);
+	f->f_back = tstate->frame;
+
+	gen->gi_running = 1;
+	result = PyEval_EvaluateFrame((PyObject *)f);
+	gen->gi_running = 0;
+
+	/* Don't keep the reference to f_back any longer than necessary.  It
+	 * may keep a chain of frames alive or it could create a reference
+	 * cycle. */
+	Py_XDECREF(f->f_back);
+	f->f_back = NULL;
+
+	/* If the generator just returned (as opposed to yielding), signal
+	 * that the generator is exhausted. */
+	if (result == Py_None && f->f_stacktop == NULL) {
+		Py_DECREF(result);
+		result = NULL;
+	}
+
+	return result;
+}
+
+static PyObject *
+gen_getiter(PyObject *gen)
+{
+	Py_INCREF(gen);
+	return gen;
+}
+
+static PyMemberDef gen_memberlist[] = {
+	{"gi_frame",	T_OBJECT, offsetof(PyGenObject, gi_frame),	RO},
+	{"gi_running",	T_INT,    offsetof(PyGenObject, gi_running),	RO},
+	{NULL}	/* Sentinel */
+};
+
+PyTypeObject PyGen_Type = {
+	PyObject_HEAD_INIT(&PyType_Type)
+	0,					/* ob_size */
+	"generator",				/* tp_name */
+	sizeof(PyGenObject),			/* tp_basicsize */
+	0,					/* tp_itemsize */
+	/* methods */
+	(destructor)gen_dealloc, 		/* tp_dealloc */
+	0,					/* tp_print */
+	0, 					/* tp_getattr */
+	0,					/* tp_setattr */
+	0,					/* tp_compare */
+	0,					/* tp_repr */
+	0,					/* tp_as_number */
+	0,					/* tp_as_sequence */
+	0,					/* tp_as_mapping */
+	0,					/* tp_hash */
+	0,					/* tp_call */
+	0,					/* tp_str */
+	PyObject_GenericGetAttr,		/* tp_getattro */
+	0,					/* tp_setattro */
+	0,					/* tp_as_buffer */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
+ 	0,					/* tp_doc */
+ 	(traverseproc)gen_traverse,		/* tp_traverse */
+ 	0,					/* tp_clear */
+	0,					/* tp_richcompare */
+	offsetof(PyGenObject, gi_weakreflist),	/* tp_weaklistoffset */
+	(getiterfunc)gen_getiter,		/* tp_iter */
+	(iternextfunc)gen_iternext,		/* tp_iternext */
+	0,					/* tp_methods */
+	gen_memberlist,				/* tp_members */
+	0,					/* tp_getset */
+	0,					/* tp_base */
+	0,					/* tp_dict */
+};
+
+PyObject *
+PyGen_New(PyFrameObject *f)
+{
+	PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
+	if (gen == NULL) {
+		Py_DECREF(f);
+		return NULL;
+	}
+	gen->gi_frame = f;
+	gen->gi_running = 0;
+	gen->gi_weakreflist = NULL;
+	_PyObject_GC_TRACK(gen);
+	return (PyObject *)gen;
+}
diff --git a/Python/ceval.c b/Python/ceval.c
index c103f14..2cebf44 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -10,6 +10,7 @@
 
 #include "compile.h"
 #include "frameobject.h"
+#include "genobject.h"
 #include "eval.h"
 #include "opcode.h"
 #include "structmember.h"
@@ -139,143 +140,6 @@ PyEval_GetCallStats(PyObject *self)
 }
 #endif
 
-static PyTypeObject gentype;
-
-typedef struct {
-	PyObject_HEAD
-	/* The gi_ prefix is intended to remind of generator-iterator. */
-
-	PyFrameObject *gi_frame;
-
-	/* True if generator is being executed. */
-	int gi_running;
-
-	/* List of weak reference. */
-	PyObject *gi_weakreflist;
-} genobject;
-
-static PyObject *
-gen_new(PyFrameObject *f)
-{
-	genobject *gen = PyObject_GC_New(genobject, &gentype);
-	if (gen == NULL) {
-		Py_DECREF(f);
-		return NULL;
-	}
-	gen->gi_frame = f;
-	gen->gi_running = 0;
-	gen->gi_weakreflist = NULL;
-	_PyObject_GC_TRACK(gen);
-	return (PyObject *)gen;
-}
-
-static int
-gen_traverse(genobject *gen, visitproc visit, void *arg)
-{
-	return visit((PyObject *)gen->gi_frame, arg);
-}
-
-static void
-gen_dealloc(genobject *gen)
-{
-	_PyObject_GC_UNTRACK(gen);
-	if (gen->gi_weakreflist != NULL)
-		PyObject_ClearWeakRefs((PyObject *) gen);
-	Py_DECREF(gen->gi_frame);
-	PyObject_GC_Del(gen);
-}
-
-static PyObject *
-gen_iternext(genobject *gen)
-{
-	PyThreadState *tstate = PyThreadState_GET();
-	PyFrameObject *f = gen->gi_frame;
-	PyObject *result;
-
-	if (gen->gi_running) {
-		PyErr_SetString(PyExc_ValueError,
-				"generator already executing");
-		return NULL;
-	}
-	if (f->f_stacktop == NULL)
-		return NULL;
-
-	/* Generators always return to their most recent caller, not
-	 * necessarily their creator. */
-	Py_XINCREF(tstate->frame);
-	assert(f->f_back == NULL);
-	f->f_back = tstate->frame;
-
-	gen->gi_running = 1;
-	result = eval_frame(f);
-	gen->gi_running = 0;
-
-	/* Don't keep the reference to f_back any longer than necessary.  It
-	 * may keep a chain of frames alive or it could create a reference
-	 * cycle. */
-	Py_XDECREF(f->f_back);
-	f->f_back = NULL;
-
-	/* If the generator just returned (as opposed to yielding), signal
-	 * that the generator is exhausted. */
-	if (result == Py_None && f->f_stacktop == NULL) {
-		Py_DECREF(result);
-		result = NULL;
-	}
-
-	return result;
-}
-
-static PyObject *
-gen_getiter(PyObject *gen)
-{
-	Py_INCREF(gen);
-	return gen;
-}
-
-static PyMemberDef gen_memberlist[] = {
-	{"gi_frame",	T_OBJECT, offsetof(genobject, gi_frame),	RO},
-	{"gi_running",	T_INT,    offsetof(genobject, gi_running),	RO},
-	{NULL}	/* Sentinel */
-};
-
-static PyTypeObject gentype = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	0,					/* ob_size */
-	"generator",				/* tp_name */
-	sizeof(genobject),			/* tp_basicsize */
-	0,					/* tp_itemsize */
-	/* methods */
-	(destructor)gen_dealloc, 		/* tp_dealloc */
-	0,					/* tp_print */
-	0, 					/* tp_getattr */
-	0,					/* tp_setattr */
-	0,					/* tp_compare */
-	0,					/* tp_repr */
-	0,					/* tp_as_number */
-	0,					/* tp_as_sequence */
-	0,					/* tp_as_mapping */
-	0,					/* tp_hash */
-	0,					/* tp_call */
-	0,					/* tp_str */
-	PyObject_GenericGetAttr,		/* tp_getattro */
-	0,					/* tp_setattro */
-	0,					/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
- 	0,					/* tp_doc */
- 	(traverseproc)gen_traverse,		/* tp_traverse */
- 	0,					/* tp_clear */
-	0,					/* tp_richcompare */
-	offsetof(genobject, gi_weakreflist),	/* tp_weaklistoffset */
-	(getiterfunc)gen_getiter,		/* tp_iter */
-	(iternextfunc)gen_iternext,		/* tp_iternext */
-	0,					/* tp_methods */
-	gen_memberlist,				/* tp_members */
-	0,					/* tp_getset */
-	0,					/* tp_base */
-	0,					/* tp_dict */
-};
-
 
 #ifdef WITH_THREAD
 
@@ -2673,7 +2537,7 @@ PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals,
 
 		/* Create a new generator that owns the ready to run frame
 		 * and return that as the value. */
-		return gen_new(f);
+		return PyGen_New(f);
 	}
 
         retval = eval_frame(f);
@@ -3407,6 +3271,12 @@ PyEval_GetFuncDesc(PyObject *func)
 	}
 }
 
+PyObject *
+PyEval_EvaluateFrame(PyObject *fo)
+{
+	return eval_frame((PyFrameObject *)fo);
+}
+
 #define EXT_POP(STACK_POINTER) (*--(STACK_POINTER))
 
 static void