bpo-41625: Expose the splice() system call in the os module (GH-21947)

1 files changed, 105 insertions, 1 deletions

diff --git a/Modules/clinic/posixmodule.c.h b/Modules/clinic/posixmodule.c.h
index f5826e3..ee4ee8c 100644
--- a/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@ -5674,6 +5674,106 @@ exit:
 
 #endif /* defined(HAVE_COPY_FILE_RANGE) */
 
+#if defined(HAVE_SPLICE)
+
+PyDoc_STRVAR(os_splice__doc__,
+"splice($module, /, src, dst, count, offset_src=None, offset_dst=None,\n"
+"       flags=0)\n"
+"--\n"
+"\n"
+"Transfer count bytes from one pipe to a descriptor or vice versa.\n"
+"\n"
+"  src\n"
+"    Source file descriptor.\n"
+"  dst\n"
+"    Destination file descriptor.\n"
+"  count\n"
+"    Number of bytes to copy.\n"
+"  offset_src\n"
+"    Starting offset in src.\n"
+"  offset_dst\n"
+"    Starting offset in dst.\n"
+"  flags\n"
+"    Flags to modify the semantics of the call.\n"
+"\n"
+"If offset_src is None, then src is read from the current position;\n"
+"respectively for offset_dst. The offset associated to the file\n"
+"descriptor that refers to a pipe must be None.");
+
+#define OS_SPLICE_METHODDEF    \
+    {"splice", (PyCFunction)(void(*)(void))os_splice, METH_FASTCALL|METH_KEYWORDS, os_splice__doc__},
+
+static PyObject *
+os_splice_impl(PyObject *module, int src, int dst, Py_ssize_t count,
+               PyObject *offset_src, PyObject *offset_dst,
+               unsigned int flags);
+
+static PyObject *
+os_splice(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"src", "dst", "count", "offset_src", "offset_dst", "flags", NULL};
+    static _PyArg_Parser _parser = {NULL, _keywords, "splice", 0};
+    PyObject *argsbuf[6];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 3;
+    int src;
+    int dst;
+    Py_ssize_t count;
+    PyObject *offset_src = Py_None;
+    PyObject *offset_dst = Py_None;
+    unsigned int flags = 0;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 6, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    src = _PyLong_AsInt(args[0]);
+    if (src == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    dst = _PyLong_AsInt(args[1]);
+    if (dst == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    {
+        Py_ssize_t ival = -1;
+        PyObject *iobj = _PyNumber_Index(args[2]);
+        if (iobj != NULL) {
+            ival = PyLong_AsSsize_t(iobj);
+            Py_DECREF(iobj);
+        }
+        if (ival == -1 && PyErr_Occurred()) {
+            goto exit;
+        }
+        count = ival;
+    }
+    if (!noptargs) {
+        goto skip_optional_pos;
+    }
+    if (args[3]) {
+        offset_src = args[3];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (args[4]) {
+        offset_dst = args[4];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+    if (!_PyLong_UnsignedInt_Converter(args[5], &flags)) {
+        goto exit;
+    }
+skip_optional_pos:
+    return_value = os_splice_impl(module, src, dst, count, offset_src, offset_dst, flags);
+
+exit:
+    return return_value;
+}
+
+#endif /* defined(HAVE_SPLICE) */
+
 #if defined(HAVE_MKFIFO)
 
 PyDoc_STRVAR(os_mkfifo__doc__,
@@ -8864,6 +8964,10 @@ exit:
     #define OS_COPY_FILE_RANGE_METHODDEF
 #endif /* !defined(OS_COPY_FILE_RANGE_METHODDEF) */
 
+#ifndef OS_SPLICE_METHODDEF
+    #define OS_SPLICE_METHODDEF
+#endif /* !defined(OS_SPLICE_METHODDEF) */
+
 #ifndef OS_MKFIFO_METHODDEF
     #define OS_MKFIFO_METHODDEF
 #endif /* !defined(OS_MKFIFO_METHODDEF) */
@@ -9059,4 +9163,4 @@ exit:
 #ifndef OS_WAITSTATUS_TO_EXITCODE_METHODDEF
     #define OS_WAITSTATUS_TO_EXITCODE_METHODDEF
 #endif /* !defined(OS_WAITSTATUS_TO_EXITCODE_METHODDEF) */
-/*[clinic end generated code: output=49b7ed768242ef7c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8a59e91178897267 input=a9049054013a1b77]*/