From 6cf8dd94050cce3288a9e2fb275dca1166fed26c Mon Sep 17 00:00:00 2001
From: Ryan Barrett <git@ryanb.org>
Date: Sun, 21 Mar 2021 15:58:01 -0700
Subject: [PATCH] add OPTIMIZED_COMMENTS constant for whether get_comments() is
 constant or linear

for snarfed/bridgy#1021
---
 granary/facebook.py  | 1 +
 granary/flickr.py    | 1 +
 granary/github.py    | 2 +-
 granary/instagram.py | 1 +
 granary/reddit.py    | 2 ++
 granary/source.py    | 5 ++++-
 granary/twitter.py   | 1 +
 7 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/granary/facebook.py b/granary/facebook.py
index 6ec939b8..a78e3431 100644
--- a/granary/facebook.py
+++ b/granary/facebook.py
@@ -214,6 +214,7 @@ class Facebook(source.Source):
   NAME = 'Facebook'
   FRONT_PAGE_TEMPLATE = 'templates/facebook_index.html'
   POST_ID_RE = re.compile('^[0-9_:]+$')  # see parse_id() for gory details
+  OPTIMIZED_COMMENTS = True
 
   # HTML snippet for embedding a post.
   # https://developers.facebook.com/docs/plugins/embedded-posts/
diff --git a/granary/flickr.py b/granary/flickr.py
index 92c9b7d3..10f389b6 100644
--- a/granary/flickr.py
+++ b/granary/flickr.py
@@ -27,6 +27,7 @@ class Flickr(source.Source):
   DOMAIN = 'flickr.com'
   BASE_URL = 'https://www.flickr.com/'
   NAME = 'Flickr'
+  OPTIMIZED_COMMENTS = False
 
   API_EXTRAS = ','.join(('date_upload', 'date_taken', 'views', 'media',
                          'description', 'tags', 'machine_tags', 'geo',
diff --git a/granary/github.py b/granary/github.py
index c1a03247..342d2a58 100644
--- a/granary/github.py
+++ b/granary/github.py
@@ -232,7 +232,7 @@ class GitHub(source.Source):
     'use_automatic_links': False,
     'tag_callback': tag_placeholders,
   }
-
+  OPTIMIZED_COMMENTS = True
 
   def __init__(self, access_token=None):
     """Constructor.
diff --git a/granary/instagram.py b/granary/instagram.py
index e3d2675f..2c7915b5 100644
--- a/granary/instagram.py
+++ b/granary/instagram.py
@@ -72,6 +72,7 @@ class Instagram(source.Source):
   BASE_URL = 'https://www.instagram.com/'
   NAME = 'Instagram'
   FRONT_PAGE_TEMPLATE = 'templates/instagram_index.html'
+  OPTIMIZED_COMMENTS = False
 
   EMBED_POST = """
   <script async defer src="//platform.instagram.com/en_US/embeds.js"></script>
diff --git a/granary/reddit.py b/granary/reddit.py
index ba2b5c77..5ad7ced3 100644
--- a/granary/reddit.py
+++ b/granary/reddit.py
@@ -22,10 +22,12 @@
 
 
 class Reddit(source.Source):
+  """Reddit source class. See file docstring and Source class for details."""
 
   DOMAIN = 'reddit.com'
   BASE_URL = 'https://reddit.com'
   NAME = 'Reddit'
+  OPTIMIZED_COMMENTS = True
 
   def __init__(self, refresh_token):
     self.refresh_token = refresh_token
diff --git a/granary/source.py b/granary/source.py
index f377826d..311e97e6 100644
--- a/granary/source.py
+++ b/granary/source.py
@@ -205,12 +205,15 @@ class Source(object, metaclass=SourceMeta):
         Defaults to Twitter's limit, 280 characters as of 2019-10-12.
   * TRUNCATE_URL_LENGTH: integer, optional. Number of characters that URLs count
         for. Defaults to Twitter's, 23 as of 2019-10-12.
+  * OPTIMIZED_COMMENTS: boolean, whether :meth:`get_comment()` is optimized and
+    only fetches the requested comment. If False, :meth:`get_comment()` fetches
+    many or all of the post's comments to find the requested one.
   """
-
   POST_ID_RE = None
   HTML2TEXT_OPTIONS = {}
   TRUNCATE_TEXT_LENGTH = None
   TRUNCATE_URL_LENGTH = None
+  OPTIMIZED_COMMENTS = False
 
   def user_url(self, user_id):
     """Returns the URL for a user's profile."""
diff --git a/granary/twitter.py b/granary/twitter.py
index 368f55cc..91d7220f 100644
--- a/granary/twitter.py
+++ b/granary/twitter.py
@@ -133,6 +133,7 @@ class Twitter(source.Source):
   NAME = 'Twitter'
   FRONT_PAGE_TEMPLATE = 'templates/twitter_index.html'
   POST_ID_RE = re.compile('^[0-9]+$')
+  OPTIMIZED_COMMENTS = True
 
   # HTML snippet for embedding a tweet.
   # https://dev.twitter.com/docs/embedded-tweets