Code to copy files/tress using hard links

First tries with a hard link and if that fails uses a normal file copy

src/calibre/utils/filenames.py

@@ -3,7 +3,7 @@ Make strings safe for use as ASCII filenames, while trying to preserve as much
 meaning as possible.
 '''
 
-import os, errno, time
+import os, errno, time, shutil
 from math import ceil
 
 from calibre import sanitize_file_name, isbytestring, force_unicode, prints
@@ -277,7 +277,7 @@ def windows_hardlink(src, dest):
         win32file.CreateHardLink(dest, src)
     except pywintypes.error as e:
         msg = u'Creating hardlink from %s to %s failed: %%s' % (src, dest)
-        raise Exception(msg % e)
+        raise OSError(msg % e)
     src_size = os.path.getsize(src)
     # We open and close dest, to ensure its directory entry is updated
     # see http://blogs.msdn.com/b/oldnewthing/archive/2011/12/26/10251026.aspx
@@ -294,7 +294,19 @@ def windows_hardlink(src, dest):
     sz = windows_get_size(dest)
     if sz != src_size:
         msg = u'Creating hardlink from %s to %s failed: %%s' % (src, dest)
-        raise Exception(msg % ('hardlink size: %d not the same as source size' % sz))
+        raise OSError(msg % ('hardlink size: %d not the same as source size' % sz))
+
+def windows_fast_hardlink(src, dest):
+    import win32file, pywintypes
+    try:
+        win32file.CreateHardLink(dest, src)
+    except pywintypes.error as e:
+        msg = u'Creating hardlink from %s to %s failed: %%s' % (src, dest)
+        raise OSError(msg % e)
+    ssz, dsz = windows_get_size(src), windows_get_size(dest)
+    if ssz != dsz:
+        msg = u'Creating hardlink from %s to %s failed: %%s' % (src, dest)
+        raise OSError(msg % ('hardlink size: %d not the same as source size: %s' % (dsz, ssz)))
 
 def windows_nlinks(path):
     import win32file
@@ -527,3 +539,59 @@ def format_permissions(st_mode):
     if st_mode & stat.S_ISVTX:
         ans[9] = 't' if (st_mode & stat.S_IXUSR) else 'T'
     return ''.join(ans)
+
+def copyfile(src, dest):
+    shutil.copyfile(src, dest)
+    try:
+        shutil.copystat(src, dest)
+    except Exception:
+        pass
+
+def get_hardlink_function(src, dest):
+    if iswindows:
+        import win32file
+        try:
+            dt = win32file.GetDriveType(dest[:2])
+        except Exception:
+            dt = win32file.DRIVE_UNKNOWN
+        hardlink = None if dt in (win32file.DRIVE_REMOTE, win32file.DRIVE_CDROM) else windows_fast_hardlink
+        hardlink = None if src[0].lower() != dest[0].lower() else hardlink
+    else:
+        hardlink = os.link
+    return hardlink
+
+def copyfile_using_links(path, dest, dest_is_dir=True, filecopyfunc=copyfile):
+    path, dest = os.path.abspath(path), os.path.abspath(dest)
+    if dest_is_dir:
+        dest = os.path.join(dest, os.path.basename(path))
+    hardlink = get_hardlink_function(path, dest)
+    try:
+        hardlink(path, dest)
+    except Exception:
+        filecopyfunc(path, dest)
+
+def copytree_using_links(path, dest, dest_is_parent=True, filecopyfunc=copyfile):
+    path, dest = os.path.abspath(path), os.path.abspath(dest)
+    if dest_is_parent:
+        dest = os.path.join(dest, os.path.basename(path))
+    hardlink = get_hardlink_function(path, dest)
+    try:
+        os.makedirs(dest)
+    except EnvironmentError as e:
+        if e.errno != errno.EEXIST:
+            raise
+    for dirpath, dirnames, filenames in os.walk(path):
+        base = os.path.relpath(dirpath, path)
+        dest_base = os.path.join(dest, base)
+        for dname in dirnames:
+            try:
+                os.mkdir(os.path.join(dest_base, dname))
+            except EnvironmentError as e:
+                if e.errno != errno.EEXIST:
+                    raise
+        for fname in filenames:
+            src, df = os.path.join(dirpath, fname), os.path.join(dest_base, fname)
+            try:
+                hardlink(src, df)
+            except Exception:
+                filecopyfunc(src, df)