9 files changed, 492 insertions, 301 deletions

diff --git a/compiler/src/Caching.hs b/compiler/src/Caching.hs
new file mode 100644
index 0000000..c2b5a43
--- /dev/null
+++ b/compiler/src/Caching.hs
@@ -0,0 +1,76 @@
+-- ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019-2020  Pacien TRAN-GIRARD
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+module Caching
+  ( Cache
+  , noCache
+  , ItemCache
+  , buildItemCache
+  , useCached
+  ) where
+
+
+import Control.Monad (when)
+import qualified Data.Map.Strict as Map
+import System.Directory (removePathForcibly, doesDirectoryExist, doesFileExist)
+
+import FileProcessors (FileProcessor)
+import Resource (GalleryItem(..), flattenGalleryTree)
+import Files
+
+
+type Cache a = FileProcessor a -> FileProcessor a
+
+
+noCache :: Cache a
+noCache processor itemPath resPath inputFsPath outputFsPath =
+  removePathForcibly outputFsPath
+  >> processor itemPath resPath inputFsPath outputFsPath
+
+
+type ItemCache = Path -> Maybe GalleryItem
+
+buildItemCache :: Maybe GalleryItem -> ItemCache
+buildItemCache cachedItems = lookupCache
+  where
+    withKey item = (webPath $ Resource.path item, item)
+    cachedItemList = maybe [] flattenGalleryTree cachedItems
+    cachedMap = Map.fromList (map withKey cachedItemList)
+    lookupCache path = Map.lookup (webPath path) cachedMap
+
+useCached :: ItemCache -> (GalleryItem -> a) -> Cache a
+useCached cache propGetter processor itemPath resPath inputFsPath outputFsPath =
+  do
+    isDir <- doesDirectoryExist outputFsPath
+    when isDir $ removePathForcibly outputFsPath
+
+    fileExists <- doesFileExist outputFsPath
+    if fileExists then
+      do
+        needUpdate <- isOutdated True inputFsPath outputFsPath
+        case (needUpdate, cache itemPath) of
+          (False, Just props) -> fromCache props
+          _ -> update
+    else
+      update
+
+  where
+    update = processor itemPath resPath inputFsPath outputFsPath
+    fromCache props =
+      putStrLn ("From cache:\t" ++ outputFsPath)
+      >> return (propGetter props)
diff --git a/compiler/src/Compiler.hs b/compiler/src/Compiler.hs
index 749872d..1ec55c5 100644
--- a/compiler/src/Compiler.hs
+++ b/compiler/src/Compiler.hs
@@ -24,17 +24,25 @@ module Compiler
 
 import GHC.Generics (Generic)
 import Control.Monad (liftM2, when)
+import Data.Bool (bool)
 import Data.Maybe (fromMaybe)
 import System.FilePath ((</>))
 import qualified System.FilePath.Glob as Glob
-import System.Directory (canonicalizePath)
+import System.Directory (canonicalizePath, doesFileExist)
 
-import Data.Aeson (ToJSON)
+import Data.Aeson (ToJSON, FromJSON)
 import qualified Data.Aeson as JSON
 
 import Config
 import Input (InputTree, readInputTree, filterInputTree, sidecar, tags)
-import Resource (GalleryItem, buildGalleryTree, galleryCleanupResourceDir)
+import Resource
+  ( GalleryItem
+  , GalleryItemProps
+  , Thumbnail
+  , buildGalleryTree
+  , galleryCleanupResourceDir
+  , properties
+  , thumbnail)
 import Files
   ( FileName
   , FSNode(..)
@@ -43,9 +51,8 @@ import Files
   , nodeName
   , filterDir
   , ensureParentDir )
-import Processors
-  ( itemFileProcessor, thumbnailFileProcessor
-  , skipCached, withCached )
+import ItemProcessors (ItemProcessor, itemFileProcessor, thumbnailFileProcessor)
+import Caching (Cache, noCache, buildItemCache, useCached)
 
 
 defaultGalleryConf :: String
@@ -64,7 +71,7 @@ thumbnailsDir = "thumbnails"
 data GalleryIndex = GalleryIndex
   { properties :: ViewerConfig
   , tree :: GalleryItem
-  } deriving (Generic, Show, ToJSON)
+  } deriving (Generic, Show, ToJSON, FromJSON)
 
 
 writeJSON :: ToJSON a => FileName -> a -> IO ()
@@ -73,6 +80,15 @@ writeJSON outputPath object =
     putStrLn $ "Generating:\t" ++ outputPath
     ensureParentDir JSON.encodeFile outputPath object
 
+loadGalleryIndex :: FilePath -> IO (Maybe GalleryIndex)
+loadGalleryIndex path =
+  doesFileExist path >>= bool (return Nothing) decodeIndex
+  where
+    decodeIndex =
+      JSON.eitherDecodeFileStrict path
+      >>= either (\err -> warn err >> return Nothing) (return . Just)
+    warn = putStrLn . ("Warning:\tUnable to reuse existing index as cache: " ++)
+
 
 (&&&) :: (a -> Bool) -> (a -> Bool) -> a -> Bool
 (&&&) = liftM2 (&&)
@@ -81,16 +97,16 @@ writeJSON outputPath object =
 (|||) = liftM2 (||)
 
 anyPattern :: [String] -> String -> Bool
-anyPattern patterns string = any (flip Glob.match string) (map Glob.compile patterns)
+anyPattern patterns string = any (flip Glob.match string . Glob.compile) patterns
 
 galleryDirFilter :: GalleryConfig -> [FilePath] -> FSNode -> Bool
 galleryDirFilter config excludedCanonicalDirs =
       (not . isHidden)
   &&& (not . isExcludedDir)
-  &&& ((matchesDir $ anyPattern $ includedDirectories config) |||
-       (matchesFile $ anyPattern $ includedFiles config))
-  &&& (not . ((matchesDir $ anyPattern $ excludedDirectories config) |||
-              (matchesFile $ anyPattern $ excludedFiles config)))
+  &&& (matchesDir (anyPattern $ includedDirectories config) |||
+       matchesFile (anyPattern $ includedFiles config))
+  &&& (not . (matchesDir (anyPattern $ excludedDirectories config) |||
+              matchesFile (anyPattern $ excludedFiles config)))
 
   where
     matchesDir :: (FileName -> Bool) -> FSNode -> Bool
@@ -102,17 +118,17 @@ galleryDirFilter config excludedCanonicalDirs =
     matchesFile _ Dir{} = False
 
     isExcludedDir :: FSNode -> Bool
-    isExcludedDir Dir{canonicalPath} = any (canonicalPath ==) excludedCanonicalDirs
+    isExcludedDir Dir{canonicalPath} = canonicalPath `elem` excludedCanonicalDirs
     isExcludedDir File{} = False
 
 inputTreeFilter :: GalleryConfig -> InputTree -> Bool
 inputTreeFilter GalleryConfig{includedTags, excludedTags} =
-      (hasTagMatching $ anyPattern includedTags)
-  &&& (not . (hasTagMatching $ anyPattern excludedTags))
+      hasTagMatching (anyPattern includedTags)
+  &&& (not . hasTagMatching (anyPattern excludedTags))
 
   where
     hasTagMatching :: (String -> Bool) -> InputTree -> Bool
-    hasTagMatching cond = (any cond) . (fromMaybe [""] . tags) . sidecar
+    hasTagMatching cond = any cond . (fromMaybe [""] . tags) . sidecar
 
 
 compileGallery :: FilePath -> FilePath -> FilePath -> FilePath -> [FilePath] -> Bool -> Bool -> IO ()
@@ -127,14 +143,17 @@ compileGallery configPath inputDirPath outputDirPath outputIndexPath excludedDir
     inputTree <- readInputTree sourceTree
     let curatedInputTree = filterInputTree (inputTreeFilter config) inputTree
 
-    let cache = if rebuildAll then skipCached else withCached
-    let itemProc = itemProcessor config cache
-    let thumbnailProc = thumbnailProcessor config cache
+    let galleryIndexPath = outputGalleryIndex outputIndexPath
+    cachedIndex <- loadCachedIndex galleryIndexPath
+    let cache = mkCache cachedIndex
+
+    let itemProc = itemProcessor config (cache Resource.properties)
+    let thumbnailProc = thumbnailProcessor config (cache Resource.thumbnail)
     let galleryBuilder = buildGalleryTree itemProc thumbnailProc (tagsFromDirectories config)
     resources <- galleryBuilder curatedInputTree
 
     when cleanOutput $ galleryCleanupResourceDir resources outputDirPath