From f181af85479fae7f0c7fec4855f0f92968d1cbcd Mon Sep 17 00:00:00 2001
From: Job Evers-Meltzer <jobevers@users.noreply.github.com>
Date: Wed, 14 Dec 2016 16:37:17 -0600
Subject: [PATCH] Cleanup code in BlobManager

---
 lbrynet/core/BlobManager.py | 57 ++++++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 19 deletions(-)

diff --git a/lbrynet/core/BlobManager.py b/lbrynet/core/BlobManager.py
index 4d174a8e7..ee688d8ae 100644
--- a/lbrynet/core/BlobManager.py
+++ b/lbrynet/core/BlobManager.py
@@ -83,6 +83,8 @@ class DiskBlobManager(BlobManager):
         self.db_conn = None
         self.blob_type = BlobFile
         self.blob_creator_type = BlobFileCreator
+        # TODO: consider using an LRU for blobs as there could potentially
+        #       be thousands of blobs loaded up, many stale
         self.blobs = {}
         self.blob_hashes_to_delete = {} # {blob_hash: being_deleted (True/False)}
         self._next_manage_call = None
@@ -295,18 +297,27 @@ class DiskBlobManager(BlobManager):
 
     @rerun_if_locked
     def _completed_blobs(self, blobs_to_check):
+        """Returns of the blobs_to_check, which are valid"""
         blobs_to_check = filter(is_valid_blobhash, blobs_to_check)
 
-        def get_blobs_in_db(db_transaction):
-            blobs_in_db = []  # [(blob_hash, last_verified_time)]
+        def _get_last_verified_time(db_transaction, blob_hash):
+            result = db_transaction.execute(
+                "select last_verified_time from blobs where blob_hash = ?", (blob_hash,))
+            row = result.fetchone()
+            if row:
+                return row[0]
+            else:
+                return None
+
+        def _filter_blobs_in_db(db_transaction, blobs_to_check):
             for b in blobs_to_check:
-                result = db_transaction.execute(
-                    "select last_verified_time from blobs where blob_hash = ?",
-                    (b,))
-                row = result.fetchone()
-                if row is not None:
-                    blobs_in_db.append((b, row[0]))
-            return blobs_in_db
+                verified_time = _get_last_verified_time(db_transaction, b)
+                if verified_time:
+                    yield (b, verified_time)
+
+        def get_blobs_in_db(db_transaction, blob_to_check):
+            # [(blob_hash, last_verified_time)]
+            return list(_filter_blobs_in_db(db_transaction, blobs_to_check))
 
         def get_valid_blobs(blobs_in_db):
 
@@ -315,23 +326,31 @@ class DiskBlobManager(BlobManager):
                 if os.path.isfile(file_path):
                     if verified_time > os.path.getctime(file_path):
                         return True
+                    else:
+                        log.debug('Verification time for %s is too old (%s < %s)',
+                                  file_path, verified_time, os.path.getctime(file_path))
+                else:
+                    log.debug('file %s does not exist', file_path)
                 return False
 
-            def return_valid_blobs(results):
-                valid_blobs = []
-                for (b, verified_date), (success, result) in zip(blobs_in_db, results):
-                    if success is True and result is True:
-                        valid_blobs.append(b)
+            def filter_valid_blobs(results):
+                assert len(blobs_in_db) == len(results)
+                valid_blobs = [
+                    b for (b, verified_date), (success, result) in zip(blobs_in_db, results)
+                    if success is True and result is True
+                ]
+                log.debug('Of %s blobs, %s were valid', len(results), len(valid_blobs))
                 return valid_blobs
 
-            ds = []
-            for b, verified_date in blobs_in_db:
-                ds.append(threads.deferToThread(check_blob_verified_date, b, verified_date))
+            ds = [
+                threads.deferToThread(check_blob_verified_date, b, verified_date)
+                for b, verified_date in blobs_in_db
+            ]
             dl = defer.DeferredList(ds)
-            dl.addCallback(return_valid_blobs)
+            dl.addCallback(filter_valid_blobs)
             return dl
 
-        d = self.db_conn.runInteraction(get_blobs_in_db)
+        d = self.db_conn.runInteraction(get_blobs_in_db, blobs_to_check)
         d.addCallback(get_valid_blobs)
         return d