-
Notifications
You must be signed in to change notification settings - Fork 3.4k
/
common.h
410 lines (348 loc) · 12.7 KB
/
common.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#pragma once
#include <functional>
#include <memory>
#include <utility>
#include "arrow/buffer.h"
#include "arrow/python/pyarrow.h"
#include "arrow/python/visibility.h"
#include "arrow/result.h"
#include "arrow/util/macros.h"
namespace arrow {
class MemoryPool;
template <class T>
class Result;
namespace py {
// Convert current Python error to a Status. The Python error state is cleared
// and can be restored with RestorePyError().
ARROW_PYTHON_EXPORT Status ConvertPyError(StatusCode code = StatusCode::UnknownError);
// Query whether the given Status is a Python error (as wrapped by ConvertPyError()).
ARROW_PYTHON_EXPORT bool IsPyError(const Status& status);
// Restore a Python error wrapped in a Status.
ARROW_PYTHON_EXPORT void RestorePyError(const Status& status);
// Catch a pending Python exception and return the corresponding Status.
// If no exception is pending, Status::OK() is returned.
inline Status CheckPyError(StatusCode code = StatusCode::UnknownError) {
if (ARROW_PREDICT_TRUE(!PyErr_Occurred())) {
return Status::OK();
} else {
return ConvertPyError(code);
}
}
#define RETURN_IF_PYERROR() ARROW_RETURN_NOT_OK(CheckPyError())
#define PY_RETURN_IF_ERROR(CODE) ARROW_RETURN_NOT_OK(CheckPyError(CODE))
// For Cython, as you can't define template C++ functions in Cython, only use them.
// This function can set a Python exception. It assumes that T has a (cheap)
// default constructor.
template <class T>
T GetResultValue(Result<T> result) {
if (ARROW_PREDICT_TRUE(result.ok())) {
return *std::move(result);
} else {
int r = internal::check_status(result.status()); // takes the GIL
assert(r == -1); // should have errored out
ARROW_UNUSED(r);
return {};
}
}
/// \brief Wrap a Result and return the corresponding Python object.
///
/// If the Result is successful, py_wrapper is called with its result value
/// and should return a PyObject*. If py_wrapper is successful (returns
/// a non-NULL value), its return value is returned.
///
/// If either the Result or py_wrapper fails, the associated Python exception
/// is raised and NULL is returned.
//
/// \param result The Result whose value to wrap in a Python object.
/// \param py_wrapper A function (likely defined in Cython) to convert the C++
/// value of the Result to a Python object.
/// \return A new Python reference, or NULL if an exception occurred
template <typename T, typename PyWrapper = PyObject* (*)(T)>
PyObject* WrapResult(Result<T> result, PyWrapper&& py_wrapper) {
static_assert(std::is_same_v<PyObject*, decltype(py_wrapper(std::declval<T>()))>,
"PyWrapper argument to WrapResult should return a PyObject* "
"when called with a T*");
Status st = result.status();
if (st.ok()) {
PyObject* py_value = py_wrapper(result.MoveValueUnsafe());
st = CheckPyError();
if (st.ok()) {
return py_value;
}
Py_XDECREF(py_value); // should be null, but who knows
}
// Status is an error, convert it to an exception.
return internal::convert_status(st);
}
// A RAII-style helper that ensures the GIL is acquired inside a lexical block.
class ARROW_PYTHON_EXPORT PyAcquireGIL {
public:
PyAcquireGIL() : acquired_gil_(false) { acquire(); }
~PyAcquireGIL() { release(); }
void acquire() {
if (!acquired_gil_) {
state_ = PyGILState_Ensure();
acquired_gil_ = true;
}
}
// idempotent
void release() {
if (acquired_gil_) {
PyGILState_Release(state_);
acquired_gil_ = false;
}
}
private:
bool acquired_gil_;
PyGILState_STATE state_;
ARROW_DISALLOW_COPY_AND_ASSIGN(PyAcquireGIL);
};
// A RAII-style helper that releases the GIL until the end of a lexical block
class ARROW_PYTHON_EXPORT PyReleaseGIL {
public:
PyReleaseGIL() { saved_state_ = PyEval_SaveThread(); }
~PyReleaseGIL() { PyEval_RestoreThread(saved_state_); }
private:
PyThreadState* saved_state_;
ARROW_DISALLOW_COPY_AND_ASSIGN(PyReleaseGIL);
};
// A helper to call safely into the Python interpreter from arbitrary C++ code.
// The GIL is acquired, and the current thread's error status is preserved.
template <typename Function>
auto SafeCallIntoPython(Function&& func) -> decltype(func()) {
PyAcquireGIL lock;
PyObject* exc_type;
PyObject* exc_value;
PyObject* exc_traceback;
PyErr_Fetch(&exc_type, &exc_value, &exc_traceback);
auto maybe_status = std::forward<Function>(func)();
// If the return Status is a "Python error", the current Python error status
// describes the error and shouldn't be clobbered.
if (!IsPyError(::arrow::internal::GenericToStatus(maybe_status)) &&
exc_type != NULLPTR) {
PyErr_Restore(exc_type, exc_value, exc_traceback);
}
return maybe_status;
}
template <typename Function>
auto SafeCallIntoPythonVoid(Function&& func) -> decltype(func()) {
PyAcquireGIL lock;
PyObject* exc_type;
PyObject* exc_value;
PyObject* exc_traceback;
PyErr_Fetch(&exc_type, &exc_value, &exc_traceback);
func();
if (exc_type != NULLPTR) {
PyErr_Restore(exc_type, exc_value, exc_traceback);
}
}
// A RAII primitive that DECREFs the underlying PyObject* when it
// goes out of scope.
class ARROW_PYTHON_EXPORT OwnedRef {
public:
OwnedRef() : obj_(NULLPTR) {}
OwnedRef(OwnedRef&& other) : OwnedRef(other.detach()) {}
explicit OwnedRef(PyObject* obj) : obj_(obj) {}
OwnedRef& operator=(OwnedRef&& other) {
obj_ = other.detach();
return *this;
}
~OwnedRef() { reset(); }
void reset(PyObject* obj) {
Py_XDECREF(obj_);
obj_ = obj;
}
void reset() { reset(NULLPTR); }
PyObject* detach() {
PyObject* result = obj_;
obj_ = NULLPTR;
return result;
}
PyObject* obj() const { return obj_; }
PyObject** ref() { return &obj_; }
operator bool() const { return obj_ != NULLPTR; }
private:
ARROW_DISALLOW_COPY_AND_ASSIGN(OwnedRef);
PyObject* obj_;
};
// Same as OwnedRef, but ensures the GIL is taken when it goes out of scope.
// This is for situations where the GIL is not always known to be held
// (e.g. if it is released in the middle of a function for performance reasons)
class ARROW_PYTHON_EXPORT OwnedRefNoGIL : public OwnedRef {
public:
OwnedRefNoGIL() : OwnedRef() {}
OwnedRefNoGIL(OwnedRefNoGIL&& other) : OwnedRef(other.detach()) {}
explicit OwnedRefNoGIL(PyObject* obj) : OwnedRef(obj) {}
~OwnedRefNoGIL() {
// This destructor may be called after the Python interpreter is finalized.
// At least avoid spurious attempts to take the GIL when not necessary.
if (obj() == NULLPTR) {
return;
}
PyAcquireGIL lock;
reset();
}
};
template <typename Fn>
struct BoundFunction;
template <typename... Args>
struct BoundFunction<void(PyObject*, Args...)> {
// We bind `cdef void fn(object, ...)` to get a `Status(...)`
// where the Status contains any Python error raised by `fn`
using Unbound = void(PyObject*, Args...);
using Bound = Status(Args...);
BoundFunction(Unbound* unbound, PyObject* bound_arg)
: unbound_(unbound), bound_arg_(bound_arg) {}
Status Invoke(Args... args) const {
PyAcquireGIL lock;
unbound_(bound_arg_.obj(), std::forward<Args>(args)...);
RETURN_IF_PYERROR();
return Status::OK();
}
Unbound* unbound_;
OwnedRefNoGIL bound_arg_;
};
template <typename Return, typename... Args>
struct BoundFunction<Return(PyObject*, Args...)> {
// We bind `cdef Return fn(object, ...)` to get a `Result<Return>(...)`
// where the Result contains any Python error raised by `fn` or the
// return value from `fn`.
using Unbound = Return(PyObject*, Args...);
using Bound = Result<Return>(Args...);
BoundFunction(Unbound* unbound, PyObject* bound_arg)
: unbound_(unbound), bound_arg_(bound_arg) {}
Result<Return> Invoke(Args... args) const {
PyAcquireGIL lock;
Return ret = unbound_(bound_arg_.obj(), std::forward<Args>(args)...);
RETURN_IF_PYERROR();
return ret;
}
Unbound* unbound_;
OwnedRefNoGIL bound_arg_;
};
template <typename OutFn, typename Return, typename... Args>
std::function<OutFn> BindFunction(Return (*unbound)(PyObject*, Args...),
PyObject* bound_arg) {
using Fn = BoundFunction<Return(PyObject*, Args...)>;
static_assert(std::is_same<typename Fn::Bound, OutFn>::value,
"requested bound function of unsupported type");
Py_XINCREF(bound_arg);
auto bound_fn = std::make_shared<Fn>(unbound, bound_arg);
return
[bound_fn](Args... args) { return bound_fn->Invoke(std::forward<Args>(args)...); };
}
// A temporary conversion of a Python object to a bytes area.
struct PyBytesView {
const char* bytes;
Py_ssize_t size;
bool is_utf8;
static Result<PyBytesView> FromString(PyObject* obj, bool check_utf8 = false) {
PyBytesView self;
ARROW_RETURN_NOT_OK(self.ParseString(obj, check_utf8));
return std::move(self);
}
static Result<PyBytesView> FromUnicode(PyObject* obj) {
PyBytesView self;
ARROW_RETURN_NOT_OK(self.ParseUnicode(obj));
return std::move(self);
}
static Result<PyBytesView> FromBinary(PyObject* obj) {
PyBytesView self;
ARROW_RETURN_NOT_OK(self.ParseBinary(obj));
return std::move(self);
}
// View the given Python object as string-like, i.e. str or (utf8) bytes
Status ParseString(PyObject* obj, bool check_utf8 = false) {
if (PyUnicode_Check(obj)) {
return ParseUnicode(obj);
} else {
ARROW_RETURN_NOT_OK(ParseBinary(obj));
if (check_utf8) {
// Check the bytes are utf8 utf-8
OwnedRef decoded(PyUnicode_FromStringAndSize(bytes, size));
if (ARROW_PREDICT_TRUE(!PyErr_Occurred())) {
is_utf8 = true;
} else {
PyErr_Clear();
is_utf8 = false;
}
}
return Status::OK();
}
}
// View the given Python object as unicode string
Status ParseUnicode(PyObject* obj) {
// The utf-8 representation is cached on the unicode object
bytes = PyUnicode_AsUTF8AndSize(obj, &size);
RETURN_IF_PYERROR();
is_utf8 = true;
return Status::OK();
}
// View the given Python object as binary-like, i.e. bytes
Status ParseBinary(PyObject* obj) {
if (PyBytes_Check(obj)) {
bytes = PyBytes_AS_STRING(obj);
size = PyBytes_GET_SIZE(obj);
is_utf8 = false;
} else if (PyByteArray_Check(obj)) {
bytes = PyByteArray_AS_STRING(obj);
size = PyByteArray_GET_SIZE(obj);
is_utf8 = false;
} else if (PyMemoryView_Check(obj)) {
PyObject* ref = PyMemoryView_GetContiguous(obj, PyBUF_READ, 'C');
RETURN_IF_PYERROR();
Py_buffer* buffer = PyMemoryView_GET_BUFFER(ref);
bytes = reinterpret_cast<const char*>(buffer->buf);
size = buffer->len;
is_utf8 = false;
} else {
return Status::TypeError("Expected bytes, got a '", Py_TYPE(obj)->tp_name,
"' object");
}
return Status::OK();
}
protected:
OwnedRef ref;
};
class ARROW_PYTHON_EXPORT PyBuffer : public Buffer {
public:
/// While memoryview objects support multi-dimensional buffers, PyBuffer only supports
/// one-dimensional byte buffers.
~PyBuffer();
static Result<std::shared_ptr<Buffer>> FromPyObject(PyObject* obj);
private:
PyBuffer();
Status Init(PyObject*);
Py_buffer py_buf_;
};
// Return the common PyArrow memory pool
ARROW_PYTHON_EXPORT void set_default_memory_pool(MemoryPool* pool);
ARROW_PYTHON_EXPORT MemoryPool* get_memory_pool();
// This is annoying: because C++11 does not allow implicit conversion of string
// literals to non-const char*, we need to go through some gymnastics to use
// PyObject_CallMethod without a lot of pain (its arguments are non-const
// char*)
template <typename... ArgTypes>
static inline PyObject* cpp_PyObject_CallMethod(PyObject* obj, const char* method_name,
const char* argspec, ArgTypes... args) {
return PyObject_CallMethod(obj, const_cast<char*>(method_name),
const_cast<char*>(argspec), args...);
}
} // namespace py
} // namespace arrow