interface to native libgamma-error code

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 200 insertions, 0 deletions

diff --git a/src/libgamma_native_error.pyx b/src/libgamma_native_error.pyx
new file mode 100644
index 0000000..f1b423c
--- /dev/null
+++ b/src/libgamma_native_error.pyx
@@ -0,0 +1,200 @@
+# -*- python -*-
+'''
+pylibgamma — Python 3 wrapper for libgamma
+Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+
+This library is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this library.  If not, see <http://www.gnu.org/licenses/>.
+'''
+
+cimport cython
+
+from posix.unistd cimport gid_t
+
+
+cdef extern int errno
+'''
+`errno` of course.
+'''
+
+
+cdef extern gid_t libgamma_group_gid
+'''
+Group that the user needs to be a member of if
+`LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned.
+'''
+
+cdef extern const char* libgamma_group_name
+'''
+Group that the user needs to be a member of if
+`LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned,
+`NULL` if the name of the group `libgamma_group_gid`
+cannot be determined.
+'''
+
+
+cdef extern void libgamma_perror(const char* name, int error_code)
+'''
+Prints an error to stderr in a `perror` fashion,
+however this function will not translate the `libgamma`
+errors into human-readable strings, it will simply
+print the name of the error. If the value `error_code`
+is the value of `LIBGAMMA_ERRNO_SET`, `perror` will be
+used to print the current error stored in `errno`.
+If `error_code` is non-negative (an `errno` value`), that
+value will be stored in `errno` and `perror` will be
+used to print it. Additionally, if the `error_code` is
+the value of `LIBGAMMA_DEVICE_REQUIRE_GROUP` the
+required group will be printed with its numerical value
+and, if known, its name.
+
+@param  name   The text to add at the beginning.
+@param  value  The error code, may be an `errno` value.
+'''
+
+cdef extern const char* libgamma_name_of_error(int value)
+'''
+Returns the name of the definition associated with a `libgamma` error code.
+
+@param   value  The error code.
+@return         The name of the definition associated with the error code,
+                `NULL` if the error code does not exist. The return string
+                should not be `free`:d.
+'''
+
+cdef extern int libgamma_value_of_error(const char* name)
+'''
+Return the value of a `libgamma` error definition refered to by name.
+
+@param   name  The name of the definition associated with the error code.
+@return        The error code, zero if the name does is `NULL`
+               or does not refer to a `libgamma` error.
+'''
+
+
+
+def libgamma_native_get_errno() -> int:
+    '''
+    Get the current value, for the current thread, of `errno`.
+    
+    @return  The value `errno`.
+    '''
+    return int(errno)
+
+
+def libgamma_native_get_group_gid() -> int:
+    '''
+    Getter.
+    
+    Group that the user needs to be a member of if
+    `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned.
+    '''
+    return int(libgamma_group_gid)
+
+def libgamma_native_set_group_gid(gid : int):
+    '''
+    Setter.
+    
+    Group that the user needs to be a member of if
+    `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned.
+    '''
+    libgamma_group_gid = <int>gid
+
+
+def libgamma_native_get_group_name() -> str:
+    '''
+    Getter.
+    
+    Group that the user needs to be a member of if
+    `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned,
+    `None` if the name of the group `libgamma_group_gid`
+    cannot be determined.
+    '''
+    cdef bytes bs
+    if libgamma_group_name == NULL:
+        return None
+    bs = libgamma_group_name
+    return bs.decode('utf-8', 'strict')
+
+def libgamma_native_set_group_name(name : str):
+    '''
+    Setter.
+    
+    Group that the user needs to be a member of if
+    `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned,
+    `None` if the name of the group `libgamma_group_gid`
+    cannot be determined.
+    '''
+    cdef bytes bs
+    if name is None:
+        libgamma_group_name = <char*>NULL
+        return
+    bs = name.encode('utf-8') + bytes([0])
+    libgamma_group_name = bs
+
+
+def libgamma_native_perror(name : str, error_code : int):
+    '''
+    Prints an error to stderr in a `perror` fashion,
+    however this function will not translate the `libgamma`
+    errors into human-readable strings, it will simply
+    print the name of the error. If the value `error_code`
+    is the value of `LIBGAMMA_ERRNO_SET`, `perror` will be
+    used to print the current error stored in `errno`.
+    If `error_code` is non-negative (an `errno` value`), that
+    value will be stored in `errno` and `perror` will be
+    used to print it. Additionally, if the `error_code` is
+    the value of `LIBGAMMA_DEVICE_REQUIRE_GROUP` the
+    required group will be printed with its numerical value
+    and, if known, its name.
+    
+    @param  name   The text to add at the beginning.
+    @param  value  The error code, may be an `errno` value.
+    '''
+    cdef bytes bs
+    bs = name.encode('utf-8') + bytes([0])
+    libgamma_perror(bs, <int>error_code)
+
+
+def libgamma_native_name_of_error(value : int) -> str:
+    '''
+    Returns the name of the definition associated with a `libgamma` error code.
+    
+    @param   value  The error code.
+    @return         The name of the definition associated with the error code,
+                    `None` if the error code does not exist. The return string
+                    should not be `free`:d.
+    '''
+    cdef const char* name
+    cdef bytes bs
+    name = libgamma_name_of_error(<int>value)
+    if name == NULL:
+        return None
+    bs = name
+    return bs.decode('utf-8', 'strict')
+
+
+def libgamma_native_value_of_error(name : str) -> int:
+    '''
+    Return the value of a `libgamma` error definition refered to by name.
+    
+    @param   name  The name of the definition associated with the error code.
+    @return        The error code, zero if the name is `None`,
+                   or does not refer to a `libgamma` error.
+    '''
+    cdef bytes bs
+    if name is None:
+        return 0
+    bs = name.encode('utf-8') + bytes([0])
+    return int(libgamma_value_of_error(bs))
+