Windows symlink: extract all system depended code to System static class

dvc/__init__.py

@@ -1,5 +0,0 @@
-from dvc.runtime import Runtime
-
-
-def setup():
-    Runtime.symlink_setup()

dvc/command/base.py

@@ -3,8 +3,7 @@
 
 from dvc.config import ConfigError
 from dvc.logger import Logger
-from dvc.path.factory import PathFactory
-from dvc.utils import cached_property
+from dvc.system import System
 
 
 class CmdBase(object):
@@ -89,7 +88,7 @@ def run(self):
         pass
 
     def get_cache_file_s3_name(self, cache_file):
-        cache_prefix_file_name = os.path.relpath(os.path.realpath(cache_file), os.path.realpath(self.git.git_dir))
+        cache_prefix_file_name = os.path.relpath(System.realpath(cache_file), System.realpath(self.git.git_dir))
         file_name = os.path.relpath(cache_prefix_file_name, self.config.cache_dir)
         dvc_file_path_trim = file_name.replace(os.sep, '/').strip('/')
         return self.config.aws_storage_prefix + '/' + dvc_file_path_trim

dvc/command/data_sync.py

@@ -7,6 +7,7 @@
 from dvc.logger import Logger
 from dvc.exceptions import DvcException
 from dvc.runtime import Runtime
+from dvc.system import System
 
 
 class DataSyncError(DvcException):
@@ -52,7 +53,7 @@ def define_args(self, parser):
         pass
 
     def run(self):
-        if os.path.islink(self.parsed_args.target):
+        if System.islink(self.parsed_args.target):
             data_item = self.path_factory.existing_data_item(self.parsed_args.target)
             return self.sync_symlink(data_item)
 
@@ -66,7 +67,7 @@ def sync_dir(self, dir):
             fname = os.path.join(dir, f)
             if os.path.isdir(fname):
                 self.sync_dir(fname)
-            elif os.path.islink(fname):
+            elif System.islink(fname):
                 self.sync_symlink(self.path_factory.existing_data_item(fname))
             else:
                 raise DataSyncError('Unsupported file type "{}"'.format(fname))

dvc/git_wrapper.py

@@ -1,10 +1,9 @@
 import os
-if os.name == 'nt':
-    from ctypes import create_unicode_buffer, windll
 
 from dvc.logger import Logger
 from dvc.config import Config
 from dvc.executor import Executor, ExecutorError
+from dvc.system import System
 
 
 class GitWrapperI(object):
@@ -22,7 +21,7 @@ def lock_file(self):
 
     @property
     def git_dir_abs(self):
-        return os.path.realpath(self.git_dir)
+        return System.realpath(self.git_dir)
 
     @property
     def curr_dir_abs(self):
@@ -51,25 +50,6 @@ def git_path_to_system_path(path):
             return path.replace('/', '\\')
         return path
 
-    LONG_PATH_BUFFER_SIZE = 1024
-
-    @staticmethod
-    def get_long_path(path):
-        """Convert short path to a full path. It is needed for Windows."""
-        if os.name != 'nt':
-            return path
-
-        buffer = create_unicode_buffer(GitWrapperI.LONG_PATH_BUFFER_SIZE)
-        get_long_path_name = windll.kernel32.GetLongPathNameW
-        result = get_long_path_name(unicode(path), buffer, GitWrapperI.LONG_PATH_BUFFER_SIZE)
-        if result == 0 or result > GitWrapperI.LONG_PATH_BUFFER_SIZE:
-            return path
-        return buffer.value
-
-    @staticmethod
-    def get_cwd():
-        return GitWrapperI.get_long_path(os.getcwd())
-
     @staticmethod
     def parse_porcelain_files(out):
         result = []
@@ -161,11 +141,11 @@ def commit_all_changes_and_log_status(self, message):
 
     @staticmethod
     def abs_paths_to_relative(files):
-        cur_dir = os.path.realpath(os.curdir)
+        cur_dir = System.realpath(os.curdir)
 
         result = []
         for file in files:
-            result.append(os.path.relpath(os.path.realpath(file), cur_dir))
+            result.append(os.path.relpath(System.realpath(file), cur_dir))
 
         return result
 

dvc/path/data_item.py

@@ -1,9 +1,9 @@
 import os
-
 import shutil
 
 from dvc.path.path import Path
 from dvc.exceptions import DvcException
+from dvc.system import System
 from dvc.utils import cached_property
 
 
@@ -100,12 +100,12 @@ def _symlink_file(self):
         return os.path.relpath(self.cache.relative, data_file_dir)
 
     def create_symlink(self):
-        os.symlink(self._symlink_file, self.data.relative)
+        System.symlink(self._symlink_file, self.data.relative)
 
     def move_data_to_cache(self):
         cache_dir = os.path.dirname(self.cache.relative)
         if not os.path.isdir(cache_dir):
             os.makedirs(cache_dir)
 
         shutil.move(self.data.relative, self.cache.relative)
-        os.symlink(self._symlink_file, self.data.relative)
+        System.symlink(self._symlink_file, self.data.relative)

dvc/path/factory.py

@@ -3,13 +3,14 @@
 from dvc.path.data_item import DataItem, DataItemError, NotInDataDirError
 from dvc.path.path import Path
 from dvc.path.stated_data_item import StatedDataItem
+from dvc.system import System
 
 
 class PathFactory(object):
     def __init__(self, git, config):
         self._git = git
         self._config = config
-        self._curr_dir_abs = os.path.realpath(os.curdir)
+        self._curr_dir_abs = System.realpath(os.curdir)
 
     def path(self, relative_raw):
         return Path(relative_raw, self._git)
@@ -24,9 +25,9 @@ def existing_data_item(self, file):
         if not os.path.exists(file):
             raise DataItemError(u'Data file "%s" is not exist' % file)
 
-        if not os.path.islink(file):
+        if not System.islink(file):
             raise DataItemError(u'Data file "%s" must be a symbolic link' % file)
-        resolved_symlink = os.path.realpath(file)
+        resolved_symlink = System.realpath(file)
         return DataItem(file, self._git, self._config, resolved_symlink)
 
     def to_data_items(self, files):

dvc/path/path.py

@@ -1,12 +1,12 @@
 import os
 
-from dvc.git_wrapper import GitWrapperI
+from dvc.system import System
 
 
 class Path(object):
     def __init__(self, path, git):
         if not os.path.isabs(path):
-            pwd = GitWrapperI.get_cwd()
+            pwd = System.get_cwd()
             path = os.path.normpath(os.path.join(pwd, path))
 
         self._abs = path

dvc/runtime.py

@@ -1,96 +1,25 @@
 import os
-import re
 import sys
-import ctypes
 
 from dvc.config import Config, ConfigI
 from dvc.exceptions import DvcException
-from dvc.executor import Executor
 from dvc.git_wrapper import GitWrapper
 from dvc.logger import Logger
 from dvc.settings import Settings
+from dvc.system import System
 
 
 class Runtime(object):
     CONFIG = 'dvc.conf'
-    SYMLINC_OVERRIDE = None
-    REALPATH_NATIVE = None
-
-    @staticmethod
-    def ls_command_name():
-        if os.name == 'nt':
-            return 'dir'
-        return 'ls'
 
     @staticmethod
     def symlink_setup():
         if os.name != 'nt':
             return
 
-        Runtime._setup_windows_symlink()
-
-        os.symlink = Runtime.symlink
-        os.path.islink = Runtime.is_link
-
-        Runtime.REALPATH_NATIVE = os.path.realpath
-        os.path.realpath = Runtime.realpath
-
-    @staticmethod
-    def _setup_windows_symlink():
-        func = ctypes.windll.kernel32.CreateSymbolicLinkW
-        func.argtypes = (ctypes.c_wchar_p, ctypes.c_wchar_p, ctypes.c_uint32)
-        func.restype = ctypes.c_ubyte
-        Runtime.SYMLINC_OVERRIDE = func
-
-    @staticmethod
-    def is_link(path):
-        if not os.path.exists(path):
-            return False
-
-        if not os.path.isfile(path):
-            return False
-
-        # It is definitely not the best way to check a symlink.
-        code, output, _ = Executor.exec_cmd(["dir", path], shell=True)
-        if code != 0:
-            return False
-
-        return '<SYMLINK>' in output
-
-    @staticmethod
-    def realpath(path):
-        if os.name != 'nt':
-            return Runtime.REALPATH_NATIVE(path)
-
-        if not os.path.islink(path):
-            return Runtime.REALPATH_NATIVE(path)
-
-        # It is definitely not the best way to check a symlink.
-        code, output, _ = Executor.exec_cmd(["dir", path], shell=True)
-        if code != 0 or not '<SYMLINK>' in output:
-            return os.path.realpath(path)
-
-        groups = re.compile(r'\[\S+\]$').findall(output.strip())
-        if len(groups) < 1:
-            return Runtime.REALPATH_NATIVE(path)
-
-        resolved_link = groups[0][1:-1]
-        return resolved_link
-
-    @staticmethod
-    def symlink(source, link_name):
-        '''symlink(source, link_name) - DVC override for Windows
-           Creates a symbolic link pointing to source named link_name'''
-
-        flags = 0
-        if source is not None and os.path.isdir(source):
-            flags = 1
-        if Runtime.SYMLINC_OVERRIDE(link_name, source, flags) == 0:
-            raise ctypes.WinError()
-
     @staticmethod
     def conf_file_path(git_dir):
-        return os.path.realpath(os.path.join(git_dir, Runtime.CONFIG))
+        return System.realpath(os.path.join(git_dir, Runtime.CONFIG))
 
     @staticmethod
     def run(cmd_class, parse_config=True):

dvc/state_file.py

@@ -4,7 +4,7 @@
 import time
 
 from dvc.exceptions import DvcException
-from dvc.git_wrapper import GitWrapperI
+from dvc.system import System
 
 
 class StateFileError(DvcException):
@@ -127,7 +127,7 @@ def normalized_args(self):
         return result
 
     def get_dvc_path(self):
-        pwd = GitWrapperI.get_cwd()
+        pwd = System.get_cwd()
         if not pwd.startswith(self.git.git_dir_abs):
             raise StateFileError('the file cannot be created outside of a git repository')
 

dvc/system.py

@@ -0,0 +1,101 @@
+import ctypes
+import os
+import re
+
+if os.name == 'nt':
+    from ctypes import create_unicode_buffer, windll
+
+from dvc.executor import Executor
+
+
+class System(object):
+    SYMLINK_OUTPUT = '<SYMLINK>'
+    LONG_PATH_BUFFER_SIZE = 1024
+
+    @staticmethod
+    def is_unix():
+        return os.name != 'nt'
+
+    @staticmethod
+    def symlink(source, link_name):
+        if System.is_unix():
+            return os.symlink(source, link_name)
+
+        flags = 0
+        if source is not None and os.path.isdir(source):
+            flags = 1
+
+        func = ctypes.windll.kernel32.CreateSymbolicLinkW
+        func.argtypes = (ctypes.c_wchar_p, ctypes.c_wchar_p, ctypes.c_uint32)
+        func.restype = ctypes.c_ubyte
+
+        if func(link_name, source, flags) == 0:
+            raise ctypes.WinError()
+
+    @staticmethod
+    def islink(path):
+        # It is definitely not the best way to check a symlink.
+
+        if System.is_unix():
+            return os.path.islink(path)
+
+        if not os.path.exists(path):
+            return False
+
+        if not os.path.isfile(path):
+            return False
+
+        return System._get_symlink_string() is not None
+
+    @staticmethod
+    def _get_symlink_string(path):
+        code, output, _ = Executor.exec_cmd(["dir", path], shell=True)
+        if code != 0:
+            return False
+
+        lines = output.split('\n')
+        for line in lines:
+            if System.SYMLINK_OUTPUT in line:
+                return line
+        return None
+
+    @staticmethod
+    def realpath(path):
+        # It is definitely not the best way to check a symlink.
+
+        if System.is_unix():
+            return os.path.realpath(path)
+
+        output = System._get_symlink_string(path)
+        if output is None:
+            return os.path.realpath(path)
+
+        groups = re.compile(r'\[\S+\]$').findall(output.strip())
+        if len(groups) < 1:
+            return os.path.realpath(path)
+
+        resolved_link = groups[0][1:-1]
+        return resolved_link
+
+    @staticmethod
+    def ls_command_name():
+        if System.is_unix():
+            return 'ls'
+        return 'dir'
+
+    @staticmethod
+    def get_long_path(path):
+        """Convert short path to a full path. It is needed for Windows."""
+        if System.is_unix():
+            return path
+
+        buffer = create_unicode_buffer(System.LONG_PATH_BUFFER_SIZE)
+        get_long_path_name = windll.kernel32.GetLongPathNameW
+        result = get_long_path_name(unicode(path), buffer, System.LONG_PATH_BUFFER_SIZE)
+        if result == 0 or result > System.LONG_PATH_BUFFER_SIZE:
+            return path
+        return buffer.value
+
+    @staticmethod
+    def get_cwd():
+        return System.get_long_path(os.getcwd())