[pypy-commit] pypy pread/pwrite: pread/pwrite

[nanjekye]

Author: Joannah Nanjekye <nanjekyejoannah at gmail.com>
Branch: pread/pwrite
Changeset: r90383:9762c2f4cd64
Date: 2017-02-18 21:03 +0300
http://bitbucket.org/pypy/pypy/changeset/9762c2f4cd64/

Log:	pread/pwrite

diff --git a/pypy/module/posix/__init__.py b/pypy/module/posix/__init__.py
--- a/pypy/module/posix/__init__.py
+++ b/pypy/module/posix/__init__.py
@@ -206,6 +206,11 @@
         interpleveldefs['get_blocking'] = 'interp_posix.get_blocking'
         interpleveldefs['set_blocking'] = 'interp_posix.set_blocking'
 
+    if hasattr(rposix, 'pread'):
+        interpleveldefs['pread'] = 'interp_posix.pread'
+    if hasattr(rposix, 'pwrite'):
+        interpleveldefs['pwrite'] = 'interp_posix.pwrite'
+        
     for _name in ["O_CLOEXEC"]:
         if getattr(rposix, _name) is not None:
             interpleveldefs[_name] = 'space.wrap(%d)' % getattr(rposix, _name)
diff --git a/pypy/module/posix/interp_posix.py b/pypy/module/posix/interp_posix.py
--- a/pypy/module/posix/interp_posix.py
+++ b/pypy/module/posix/interp_posix.py
@@ -269,7 +269,7 @@
         raise wrap_oserror(space, e)
     else:
         return space.newbytes(s)
-
+        
 @unwrap_spec(fd=c_int)
 def write(space, fd, w_data):
     """Write a string to a file descriptor.  Return the number of bytes
@@ -282,6 +282,25 @@
     else:
         return space.wrap(res)
 
+ at unwrap_spec(fd=c_int, length=int, offset=int)
+def pread(space, fd, length, offset):
+    try:
+        s = rposix.pread(fd, length, offset)
+    except OSError as e:
+        raise wrap_oserror(space, e)
+    else:
+        return space.newbytes(s)
+
+ at unwrap_spec(fd=c_int, offset=int)
+def pwrite(space, fd, w_data, offset):
+    data = space.getarg_w('y*', w_data)
+    try:
+        res = rposix.pwrite(fd, data.as_str(), offset)
+    except OSError as e:
+        raise wrap_oserror(space, e)
+    else:
+        return space.wrap(res)
+
 @unwrap_spec(fd=c_int)
 def close(space, fd):
     """Close a file descriptor (for low level IO)."""
diff --git a/pypy/module/posix/test/test_posix2.py b/pypy/module/posix/test/test_posix2.py
--- a/pypy/module/posix/test/test_posix2.py
+++ b/pypy/module/posix/test/test_posix2.py
@@ -833,6 +833,30 @@
                     os.chdir(localdir)
             raises(ValueError, os.fchdir, -1)
 
+    if hasattr(rposix, 'pread'):
+        def test_os_pread(self):
+            os = self.posix
+            fd = os.open(self.path2 + 'test_os_pread', os.O_RDWR | os.O_CREAT)
+            try:
+                os.write(fd, b'test')
+                os.lseek(fd, 0, os.SEEK_SET)
+                assert os.pread(fd, 2, 1) == b'es'
+                assert os.read(fd, 2) == b'te'
+            finally:
+                os.close(fd)
+
+    if hasattr(rposix, 'pwrite'):
+        def test_os_pwrite(self):
+            os = self.posix
+            fd = os.open(self.path2 + 'test_os_pwrite', os.O_RDWR | os.O_CREAT)
+            try:
+                os.write(fd, b'test')
+                os.lseek(fd, 0, os.SEEK_SET)
+                os.pwrite(fd, b'xx', 1)
+                assert os.read(fd, 4) == b'txxt'
+            finally:
+                os.close(fd)
+                
     def test_largefile(self):
         os = self.posix
         fd = os.open(self.path2 + 'test_largefile',
diff --git a/rpython/rlib/rposix.py b/rpython/rlib/rposix.py
--- a/rpython/rlib/rposix.py
+++ b/rpython/rlib/rposix.py
@@ -485,6 +485,31 @@
 def sync():
     c_sync()
 
+c_pread = external('pread',
+                  [rffi.INT, rffi.VOIDP, rffi.SIZE_T , rffi.LONGLONG], rffi.SSIZE_T,
+                  save_err=rffi.RFFI_SAVE_ERRNO)
+c_pwrite = external('pwrite',
+                   [rffi.INT, rffi.VOIDP, rffi.SIZE_T, rffi.LONGLONG], rffi.SSIZE_T,
+                   save_err=rffi.RFFI_SAVE_ERRNO)
+
+ at replace_os_function('pread')
+ at enforceargs(int, int, None)
+def pread(fd, count, offset):
+    if count < 0:
+        raise OSError(errno.EINVAL, None)
+    validate_fd(fd)
+    with rffi.scoped_alloc_buffer(count) as buf:
+        void_buf = rffi.cast(rffi.VOIDP, buf.raw)
+        return buf.str(handle_posix_error('pread', c_pread(fd, void_buf, count, offset)))
+
+ at replace_os_function('pwrite')
+ at enforceargs(int, None, None)
+def pwrite(fd, data, offset):
+    count = len(data)
+    validate_fd(fd)
+    with rffi.scoped_nonmovingbuffer(data) as buf:
+        return handle_posix_error('pwrite', c_pwrite(fd, buf, count, offset))
+
 #___________________________________________________________________
 
 c_chdir = external('chdir', [rffi.CCHARP], rffi.INT,