X.P: Add escape hatch for preventing X.P IO

CHANGES.md

@@ -13,6 +13,13 @@
        order to lift any existing `IO StatusBarConfig` values into
        `X StatusBarConfig` values.
 
+  * `XMonad.Prompt`
+
+    - Added an additional `XPConfig` argument to `historyCompletion` and
+      `historyCompletionP`. Calls along the lines of `historyCompletionP
+      myFunc` should be changed to `historyCompletionP myConf myFunc`.
+      If not `myConf` is lying around, `def` can be used instead.
+
 ### New Modules
 
   * `XMonad.Actions.Profiles`.
@@ -37,6 +44,11 @@
 
     - Added `HH:MM-HH:MM` and `HH:MM+HH` syntax to specify time spans.
 
+  * `XMonad.Prompt`
+
+    - The history file is not extraneously read and written anymore if
+      the `historySize` is set to 0.
+
 ### Other changes
 
 ## 0.18.0 (February 3, 2024)

XMonad/Actions/Search.hs

@@ -437,14 +437,14 @@ namedEngine name (SearchEngine _ site) = searchEngineF name site
    browser. -}
 promptSearchBrowser :: XPConfig -> Browser -> SearchEngine -> X ()
 promptSearchBrowser config browser (SearchEngine name site) = do
-    hc <- historyCompletionP ("Search [" `isPrefixOf`)
+    hc <- historyCompletionP config ("Search [" `isPrefixOf`)
     mkXPrompt (Search name) config hc $ search browser site
 
 {- | Like 'promptSearchBrowser', but only suggest previous searches for the
    given 'SearchEngine' in the prompt. -}
 promptSearchBrowser' :: XPConfig -> Browser -> SearchEngine -> X ()
 promptSearchBrowser' config browser (SearchEngine name site) = do
-    hc <- historyCompletionP (searchName `isPrefixOf`)
+    hc <- historyCompletionP config (searchName `isPrefixOf`)
     mkXPrompt (Search name) config hc $ search browser site
   where
     searchName = showXPrompt (Search name)

XMonad/Actions/WorkspaceNames.hs

@@ -138,7 +138,7 @@ setCurrentWorkspaceName name = do
 -- | Prompt for a new name for the current workspace and set it.
 renameWorkspace :: XPConfig -> X ()
 renameWorkspace conf = do
-    completion <- historyCompletionP (prompt ==)
+    completion <- historyCompletionP conf (prompt ==)
     mkXPrompt (Wor prompt) conf completion setCurrentWorkspaceName
   where
     prompt = "Workspace name: "

XMonad/Prompt.hs

@@ -562,7 +562,7 @@ mkXPromptImplementation historyKey conf om = do
   s <- gets $ screenRect . W.screenDetail . W.current . windowset
   cleanMask <- cleanKeyMask
   cachedir <- asks (cacheDir . directories)
-  hist <- io $ readHistory cachedir
+  hist <- io $ readHistory conf cachedir
   fs <- initXMF (font conf)
   let width = getWinWidth s (position conf)
   st' <- io $
@@ -582,7 +582,7 @@ mkXPromptImplementation historyKey conf om = do
   releaseXMF fs
   when (successful st') $ do
     let prune = take (historySize conf)
-    io $ writeHistory cachedir $
+    io $ writeHistory conf cachedir $
       M.insertWith
       (\xs ys -> prune . historyFilter conf $ xs ++ ys)
       historyKey
@@ -1690,16 +1690,18 @@ emptyHistory = M.empty
 getHistoryFile :: FilePath -> FilePath
 getHistoryFile cachedir = cachedir ++ "/prompt-history"
 
-readHistory :: FilePath -> IO History
-readHistory cachedir = readHist `E.catch` \(SomeException _) -> return emptyHistory
+readHistory :: XPConfig -> FilePath -> IO History
+readHistory (XPC { historySize = 0 }) _ = return emptyHistory
+readHistory _ cachedir = readHist `E.catch` \(SomeException _) -> return emptyHistory
  where
     readHist = do
         let path = getHistoryFile cachedir
         xs <- withFile path ReadMode hGetLine
         readIO xs
 
-writeHistory :: FilePath -> History -> IO ()
-writeHistory cachedir hist = do
+writeHistory :: XPConfig -> FilePath -> History -> IO ()
+writeHistory (XPC { historySize = 0 }) _ _ = return ()
+writeHistory _ cachedir hist = do
   let path = getHistoryFile cachedir
       filtered = M.filter (not . null) hist
   writeFile path (show filtered) `E.catch` \(SomeException e) ->
@@ -1793,17 +1795,17 @@ breakAtSpace s
 -- | 'historyCompletion' provides a canned completion function much like
 --   'getShellCompl'; you pass it to mkXPrompt, and it will make completions work
 --   from the query history stored in the XMonad cache directory.
-historyCompletion :: X ComplFunction
-historyCompletion = historyCompletionP (const True)
+historyCompletion :: XPConfig -> X ComplFunction
+historyCompletion conf = historyCompletionP conf (const True)
 
 -- | Like 'historyCompletion' but only uses history data from Prompts whose
 -- name satisfies the given predicate.
-historyCompletionP :: (String -> Bool) -> X ComplFunction
-historyCompletionP p = do
+historyCompletionP :: XPConfig -> (String -> Bool) -> X ComplFunction
+historyCompletionP conf p = do
     cd <- asks (cacheDir . directories)
     pure $ \x ->
         let toComplList = deleteConsecutive . filter (isInfixOf x) . M.foldr (++) []
-         in toComplList . M.filterWithKey (const . p) <$> readHistory cd
+         in toComplList . M.filterWithKey (const . p) <$> readHistory conf cd
 
 -- | Sort a list and remove duplicates. Like 'deleteAllDuplicates', but trades off
 --   laziness and stability for efficiency.