From 9b5c8368daa97a5b58a378d9c4eab66ebb018cb0 Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Sat, 28 Dec 2024 21:49:02 +0530
Subject: Fix memory leak issue with c++ interop

---
 TODO.norg             | 2 +-
 cpp/libchelleport.cpp | 2 +-
 flake.nix             | 1 +
 src/Chelleport/OCR.hs | 7 ++++---
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/TODO.norg b/TODO.norg
index d71d249..2228e2d 100644
--- a/TODO.norg
+++ b/TODO.norg
@@ -1,11 +1,11 @@
 * Current
+  - ( ) Investigate memory leak with c++ ffi when re-evaluating ocr
   - ( ) TextStyle for drawText
   - ( ) Middle click
   - (-) Optimize speed of ocr
   - ( ) Backspace deletes a single character in search mode
 
 * Later
-  - ( ) Separate state for hint modes into ModeHint constructor
   - ( ) Look into making mouse controls (click/mouse down/mouse up) cross-platform
   - ( ) Look into making screenshot cross-platform
   - ( ) Lens-ey setup for Mode access
diff --git a/cpp/libchelleport.cpp b/cpp/libchelleport.cpp
index 53ba64e..010fdd4 100644
--- a/cpp/libchelleport.cpp
+++ b/cpp/libchelleport.cpp
@@ -13,7 +13,7 @@ extern "C" OCRMatch *findWordCoordinates(const char *image_path, int *size) {
   OCRMatchSet matches;
   MEASURE("OCR", { matches = extractTextMatches(image_path); });
 
-  static OCRMatch *ptr = new OCRMatch[matches.size()];
+  OCRMatch *ptr = new OCRMatch[matches.size()];
   std::copy(matches.begin(), matches.end(), ptr);
 
   *size = matches.size();
diff --git a/flake.nix b/flake.nix
index 3486cff..93f0551 100644
--- a/flake.nix
+++ b/flake.nix
@@ -47,6 +47,7 @@
             just
             nodemon
             clang-tools
+            valgrind
           ];
         in {
           haskellProjects.default = {
diff --git a/src/Chelleport/OCR.hs b/src/Chelleport/OCR.hs
index 64c69e5..43ab34d 100644
--- a/src/Chelleport/OCR.hs
+++ b/src/Chelleport/OCR.hs
@@ -5,7 +5,7 @@ import Control.Concurrent (threadDelay)
 import Control.Monad.IO.Class (MonadIO (liftIO))
 import Control.Monad.RWS (MonadReader (ask))
 import qualified Data.ByteString as BS
-import Foreign (Bits (shiftR), Ptr, Storable (peek, pokeByteOff), alloca, allocaBytes, peekArray, (.&.))
+import Foreign (Bits (shiftR), Ptr, Storable (peek, pokeByteOff), alloca, allocaBytes, free, peekArray, (.&.))
 import Foreign.C (CInt, CString, newCString)
 import GHC.IO.Handle.FD (withFile)
 import GHC.IO.IOMode (IOMode (WriteMode))
@@ -31,7 +31,6 @@ instance (MonadIO m) => MonadOCR (AppM m) where
       pure path
 
   getWordsInImage filePath = liftIO $ do
-    -- result `seq` pure result -- Strict eval
     findWordCoordinates filePath <* removeFile filePath
 
 findWordCoordinates :: String -> IO [OCRMatch]
@@ -40,7 +39,9 @@ findWordCoordinates imgPath = alloca $ \sizePtr -> do
   arrayPtr <- c_getAllWordCoordinates imgPathC sizePtr
 
   size <- peek sizePtr
-  peekArray (fromIntegral size) arrayPtr
+  result <- peekArray (fromIntegral size) arrayPtr
+  free arrayPtr
+  pure result
 
 createTemporaryScreenshot :: DrawContext -> (CInt, CInt) -> (CInt, CInt) -> IO String
 createTemporaryScreenshot ctx offset size = do
-- 
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