feat: add hash_cache

modules/hash_cache.py

@@ -0,0 +1,41 @@
+from modules.util import sha256, HASH_SHA256_LENGTH
+import os
+import json
+hash_cache_filename = 'hash_cache.json'
+hash_cache = {}
+
+
+def sha256_from_cache(filepath):
+    global hash_cache
+    if filepath not in hash_cache:
+        hash_cache[filepath] = sha256(filepath)
+        save_cache_to_file()
+
+    return hash_cache[filepath]
+
+
+def load_cache_from_file():
+    global hash_cache
+
+    try:
+        if os.path.exists(hash_cache_filename):
+            with open(hash_cache_filename, 'rt', encoding='utf-8') as fp:
+                for filepath, hash in json.load(fp).items():
+                    if not os.path.exists(filepath) or not isinstance(hash, str) and len(hash) != HASH_SHA256_LENGTH:
+                        print(f'[Cache] Skipping invalid cache entry: {filepath}')
+                        continue
+                    hash_cache[filepath] = hash
+            print(f'[Cache] Warmed cache from file')
+    except Exception as e:
+        print(f'[Cache] Warming failed: {e}')
+
+
+def save_cache_to_file():
+    global hash_cache
+
+    try:
+        with open(hash_cache_filename, 'wt', encoding='utf-8') as fp:
+            json.dump(hash_cache, fp, indent=4)
+        print(f'[Cache] Updated cache file')
+    except Exception as e:
+        print(f'[Cache] Saving failed: {e}')