From 9e5bdace2c75eb6436ad33fc8908b1dd4df29c93 Mon Sep 17 00:00:00 2001
From: Philip Sargent <philip.sargent@klebos.com>
Date: Wed, 5 Oct 2022 21:10:05 +0300
Subject: [PATCH] make cache work even if timestamps wrong

---
 parsers/logbooks.py | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/parsers/logbooks.py b/parsers/logbooks.py
index d693b9a..8fc78d6 100644
--- a/parsers/logbooks.py
+++ b/parsers/logbooks.py
@@ -585,15 +585,19 @@ def LoadLogbookForExpedition(expedition):
     expect = entries[year]
     # print(" - Logbook for: " + year)
 
-    def validcache(year,n):
+    def validcache(year,n, lbsize):
         if year != expedition:
-            print("   ! year != expedition ",year, expedition )
+            print("   ! cache loading: year != expedition ",year, expedition )
+            return False
+        currentsize = logbookpath.stat().st_size
+        if lbsize != currentsize:
+            print(f"   ! cache loading: Logbook size {lbsize} != {currentsize} ")
             return False
         if len(logentries) != n:
-            print("   ! len(logentries) != n ",len(logentries), n )
+            print("   ! cache loading: len(logentries) != n ",len(logentries), n )
             return False
         if n != expect:
-            print("   ! n != expect ",n, expect )
+            print("   ! cache loading: n != expect ",n, expect )
             return False
         return True
     
@@ -652,15 +656,15 @@ def LoadLogbookForExpedition(expedition):
             try:
                 # print("   - Reading cache: " + str(cache_filename), end='')
                 with open(cache_filename, "rb") as f:
-                    year,n,logentries = pickle.load(f) 
-                if validcache(year,n):
+                    year, lbsize, n, logentries = pickle.load(f) 
+                if validcache(year, n, lbsize):
                     print(f"  -- {year} : Loaded {len(logentries)} log entries")
                     logbook_cached = True
                 else:
-                    print("  !- Told to expect ", expect, " but ", len(logentries), " found in cache")
+                    print("  !- {year} : Cache failed validity checks")
                     raise
             except:
-                print("   ! Failed to load corrupt cache.  (Or I was told to ignore it). Deleting it.")
+                print("   ! Failed to load corrupt cache  (or I was told to ignore it). Deleting it.")
                 os.remove(cache_filename)
                 logentries=[]
                 raise
@@ -684,8 +688,9 @@ def LoadLogbookForExpedition(expedition):
         SetDatesFromLogbookEntries(expedition)
         if len(logentries) >0:
             print("   - Cacheing " , len(logentries), " log entries")
+            lbsize = logbookpath.stat().st_size
             with open(cache_filename, "wb") as fc: # we much check that permission are g+w ! or expo can't delete the cache
-                logbk=(expedition,len(logentries),logentries)
+                logbk=(expedition,lbsize,len(logentries),logentries)
                 pickle.dump(logbk, fc, protocol=4)
         else:
             print("   ! NO TRIP entries found in logbook, check the syntax.")
@@ -737,7 +742,7 @@ def LoadLogbooks():
     expd ={}
     actuals = []
     
-    for expo in expos:
+    for expo in expos: # pointless as we explicitly know the years in this code.
         year = expo.year
         TROG['pagecache']['expedition'][year] = None # clear cache
         if year in sqlfail: