implement 'enumerate' for 'extractor.skip' (#306)

[ci skip]

docs/configuration.rst

@@ -131,8 +131,11 @@ extractor.*.skip
 =========== =====
 Type        ``bool`` or ``string``
 Default     ``true``
-Description Controls the behavior when downloading files whose filename
-            already exists.
+Description Controls the behavior when downloading files that have been
+            downloaded before, i.e. a file with the same filename already
+            exists or its ID is in a `download archive`__.
+
+            __ `extractor.*.archive`_
 
             * ``true``: Skip downloads
             * ``false``: Overwrite already existing files
@@ -144,6 +147,9 @@ Description Controls the behavior when downloading files whose filename
             * ``"exit"``: Exit the program altogether
             * ``"exit:N"``: Skip downloads and exit the program
               after ``N`` consecutive skips
+
+            * ``"enumerate"``: Append a numeric suffix to the end of the
+              original filename (``file.ext.1``, ``file.ext.2``, etc)
 =========== =====
 
 

gallery_dl/job.py

@@ -316,7 +316,9 @@ class DownloadJob(Job):
         skip = self.extractor.config("skip", True)
         if skip:
             self._skipexc = None
-            if isinstance(skip, str):
+            if skip == "enumerate":
+                self.pathfmt.check_file = self.pathfmt._enum_file
+            elif isinstance(skip, str):
                 skip, _, smax = skip.partition(":")
                 if skip == "abort":
                     self._skipexc = exception.StopExtraction

gallery_dl/util.py

@@ -529,6 +529,7 @@ class PathFormat():
         self.filename = ""
         self.directory = self.realdirectory = ""
         self.path = self.realpath = self.temppath = ""
+        self.suffix = ""
 
         self.basedirectory = expand_path(
             extractor.config("base-directory", (".", "gallery-dl")))
@@ -565,9 +566,25 @@ class PathFormat():
         if archive and archive.check(self.keywords):
             return self.fix_extension()
         if self.has_extension and os.path.exists(self.realpath):
-            return True
+            return self.check_file()
         return False
 
+    @staticmethod
+    def check_file():
+        return True
+
+    def _enum_file(self):
+        num = 1
+        while True:
+            suffix = "." + str(num)
+            rpath = self.realpath + suffix
+            if not os.path.exists(rpath):
+                self.path += suffix
+                self.realpath = rpath
+                self.suffix = suffix
+                return False
+            num += 1
+
     def set_directory(self, keywords):
         """Build directory path and create it if necessary"""
         try:
@@ -596,7 +613,7 @@ class PathFormat():
     def set_keywords(self, keywords):
         """Set filename keywords"""
         self.keywords = keywords
-        self.temppath = ""
+        self.temppath = self.suffix = ""
         self.has_extension = bool(keywords.get("extension"))
         if self.has_extension:
             self.build_path()
@@ -623,7 +640,7 @@ class PathFormat():
         except Exception as exc:
             raise exception.FormatError(exc, "filename")
 
-        filename = os.sep + self.filename
+        filename = os.sep + self.filename + self.suffix
         self.path = self.directory + filename
         self.realpath = self.realdirectory + filename
         if not self.temppath: