utils.py: Add filter_callback parameter to copy_files and link_files

1 files changed, 21 insertions, 4 deletions

diff --git a/buildstream/utils.py b/buildstream/utils.py
index 204afca0c..37bcfbeed 100644
--- a/buildstream/utils.py
+++ b/buildstream/utils.py
@@ -352,12 +352,16 @@ def safe_remove(path):
                         .format(path, e))
 
 
-def copy_files(src, dest, *, files=None, ignore_missing=False, report_written=False):
+def copy_files(src, dest, *, filter_callback=None, files=None, ignore_missing=False, report_written=False):
     """Copy files from source to destination.
 
     Args:
        src (str): The source file or directory
        dest (str): The destination directory
+       filter_callback (callable): Optional filter callback. Called with the relative path as
+                                   argument for every file in the source directory. The file is
+                                   copied only if the callable returns True. If no filter callback
+                                   is specified, all files will be copied.
        files (list): Optional list of files in `src` to copy
        ignore_missing (bool): Dont raise any error if a source file is missing
        report_written (bool): Add to the result object the full list of files written
@@ -383,7 +387,9 @@ def copy_files(src, dest, *, files=None, ignore_missing=False, report_written=Fa
 
     result = FileListResult()
     try:
-        _process_list(src, dest, files, safe_copy, result, ignore_missing=ignore_missing,
+        _process_list(src, dest, files, safe_copy, result,
+                      filter_callback=filter_callback,
+                      ignore_missing=ignore_missing,
                       report_written=report_written, presorted=presorted)
     except OSError as e:
         raise UtilError("Failed to copy '{} -> {}': {}"
@@ -391,12 +397,16 @@ def copy_files(src, dest, *, files=None, ignore_missing=False, report_written=Fa
     return result
 
 
-def link_files(src, dest, *, files=None, ignore_missing=False, report_written=False):
+def link_files(src, dest, *, filter_callback=None, files=None, ignore_missing=False, report_written=False):
     """Hardlink files from source to destination.
 
     Args:
        src (str): The source file or directory
        dest (str): The destination directory
+       filter_callback (callable): Optional filter callback. Called with the relative path as
+                                   argument for every file in the source directory. The file is
+                                   hardlinked only if the callable returns True. If no filter
+                                   callback is specified, all files will be hardlinked.
        files (list): Optional list of files in `src` to link
        ignore_missing (bool): Dont raise any error if a source file is missing
        report_written (bool): Add to the result object the full list of files written
@@ -427,7 +437,9 @@ def link_files(src, dest, *, files=None, ignore_missing=False, report_written=Fa
 
     result = FileListResult()
     try:
-        _process_list(src, dest, files, safe_link, result, ignore_missing=ignore_missing,
+        _process_list(src, dest, files, safe_link, result,
+                      filter_callback=filter_callback,
+                      ignore_missing=ignore_missing,
                       report_written=report_written, presorted=presorted)
     except OSError as e:
         raise UtilError("Failed to link '{} -> {}': {}"
@@ -810,11 +822,13 @@ def _ensure_real_directory(root, path):
 #    filelist: List of relative file paths
 #    actionfunc: The function to call for regular files
 #    result: The FileListResult
+#    filter_callback: Optional callback to invoke for every directory entry
 #    ignore_missing: Dont raise any error if a source file is missing
 #    presorted: Whether the passed list is known to be presorted
 #
 #
 def _process_list(srcdir, destdir, filelist, actionfunc, result,
+                  filter_callback=None,
                   ignore_missing=False, report_written=False,
                   presorted=False):
 
@@ -822,6 +836,9 @@ def _process_list(srcdir, destdir, filelist, actionfunc, result,
     # *after* files have been written.
     permissions = []
 
+    if filter_callback:
+        filelist = [path for path in filelist if filter_callback(path)]
+
     # Sorting the list of files is necessary to ensure that we processes
     # symbolic links which lead to directories before processing files inside
     # those directories.