implemented link subcommand

filetags.py

@@ -200,6 +200,8 @@ if __name__ == "__main__":
   #TODO: clarification of <> and []
   #TODO: subcommand to change container settings
   VALID_COMMANDS=["create", "add", "remove", "search", "lookup", "link", "check", "update", "fix", "help"]
+  #TODO: (*fully) implemented subcommands: *create, *add, *lookup, *help
+  #TODO: unimplemented subcommands: remove, search, link, check, update, fix
 
   try:
     command = sys.argv[1].split("+")
@@ -212,11 +214,6 @@ if __name__ == "__main__":
     print(USAGE, file=sys.stderr)
     sys.exit(USAGE_ERROR)
 
-  # help subcommand
-  if command[0] == "help":
-    print(USAGE)
-    sys.exit(0)
-
   # create subcommand: create a new directory containing a folder for stored objects, one for parity files and one for
   # arguments: <storage directory> [parity=<on|off>] [parity-bytes=<number of bytes for each parity byte>] [checksum-algorithm=<algorithm>] [compress=<on|off>]
   if command[0] == "create":
@@ -400,6 +397,48 @@ if __name__ == "__main__":
     else:
       print(json.dumps(lookup_results))
 
+  # link subcommand: add a symlink in <location> that points to the referenced file
+  # arguments:
+  #  <storage directory> <hash> <location>
+  if command[0] == "link":
+    if len(sys.argv)<5:
+      print("Too few arguments!", file=sys.stderr)
+      print(USAGE, file=sys.stderr)
+      sys.exit(USAGE_ERROR)
+
+    storage_directory = sys.argv[2]
+    file_hash = sys.argv[3]
+    link_location = sys.argv[4]
+    status, parity, parity_bytes, checksum_algorithm, compress = load_container_settings(storage_directory)
+    if not status==0:
+      if status==PATH_ERROR:
+        print("Invalid storage directory!", file=sys.stderr)
+        print(USAGE, file=sys.stderr)
+      if status==GENERAL_ERROR:
+        print("Verifying container settings failed.", file=sys.stderr)
+      sys.exit(status)
+
+    if file_hash_or_path_is_known_hash(storage_directory, file_hash, compress):
+      if os.path.isdir(os.sep.join(link_location.split(os.sep)[:-1])):
+        if os.path.exists(link_location):
+          print(link_location+": file already exists.", file=sys.stderr)
+          sys.exit(GENERAL_ERROR)
+        else:
+          suffix = ""
+          if compress:
+            suffix = ".xz"
+          object_path = os.path.join(storage_directory, "objects", file_hash+suffix)
+          os.symlink(object_path, link_location)
+          print(link_location+" -> "+object_path)
+      else:
+        print("Parent directory "+os.sep.join(link_location.split(os.sep)[:-1])+" does not exist.", file=sys.stderr)
+        sys.exit(GENERAL_ERROR)
+
+  # help subcommand
+  if command[0] == "help":
+    print(USAGE)
+    sys.exit(0)
+
 
 
 # this line is here to work around a bug in Xed