From b140f249c146113e165078c40111a228f04e7a72 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Koutensk=C3=BD?= <koutak.m@gmail.com>
Date: Mon, 19 Feb 2018 10:45:47 +0100
Subject: [PATCH] Allow plugins to define early import stage functions

---
 beets/importer.py |  2 ++
 beets/plugins.py  | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/beets/importer.py b/beets/importer.py
index aac21d77f0..4e4084eec0 100644
--- a/beets/importer.py
+++ b/beets/importer.py
@@ -313,6 +313,8 @@ def run(self):
                 stages += [import_asis(self)]
 
             # Plugin stages.
+            for stage_func in plugins.early_import_stages():
+                stages.append(plugin_stage(self, stage_func))
             for stage_func in plugins.import_stages():
                 stages.append(plugin_stage(self, stage_func))
 
diff --git a/beets/plugins.py b/beets/plugins.py
index d62f3c011e..ace5170e31 100644
--- a/beets/plugins.py
+++ b/beets/plugins.py
@@ -81,6 +81,7 @@ def __init__(self, name=None):
             self.template_fields = {}
         if not self.album_template_fields:
             self.album_template_fields = {}
+        self.early_import_stages = []
         self.import_stages = []
 
         self._log = log.getChild(self.name)
@@ -94,6 +95,17 @@ def commands(self):
         """
         return ()
 
+    def get_early_import_stages(self):
+        """Return a list of functions that should be called as importer
+        pipelines stages early in the pipeline.
+
+        The callables are wrapped versions of the functions in
+        `self.early_import_stages`. Wrapping provides some bookkeeping for the
+        plugin: specifically, the logging level is adjusted to WARNING.
+        """
+        return [self._set_log_level_and_params(logging.WARNING, import_stage)
+                for import_stage in self.early_import_stages]
+
     def get_import_stages(self):
         """Return a list of functions that should be called as importer
         pipelines stages.
@@ -393,6 +405,14 @@ def template_funcs():
     return funcs
 
 
+def early_import_stages():
+    """Get a list of early import stage functions defined by plugins."""
+    stages = []
+    for plugin in find_plugins():
+        stages += plugin.get_early_import_stages()
+    return stages
+
+
 def import_stages():
     """Get a list of import stage functions defined by plugins."""
     stages = []