snippet: unused Monero mapping

tools/snippets/README.md

@@ -5,12 +5,15 @@ This folder is storing non-essential scripts (snippets, gists), which may howeve
 
 These scripts do not need to have a high standard, but each of those should have a short description of what is it doing.
 
-## sign_tx.py - [file](./sign_tx.py)
+## [sign_tx.py](./sign_tx.py)
 - signing of BTC transactions that can be spent with currently connected device
 - need to specify the input UTXOs and the output address(es)
 - generates a serialized transaction that can be then announced to the network
 
-## unify_test_files.py - [file](./unify_test_files.py)
+## [unify_test_files.py](./unify_test_files.py)
 - enforcing some readability practices in test files and possibly adding information about paths and addresses used
 - need to specify all the files to be modified and optionally the path-to-address translation file
 - rewrites the files in place, or just prints the intended changes when run with `-c`
+
+## [monero_unused_functions](./monero_unused_functions.py)
+- Find functions from Monero cryptography that are not used.

tools/snippets/monero_unused_functions.py

@@ -0,0 +1,110 @@
+"""
+Find out which functions are unused in the Monero app - based on
+`monero.pyi` file.
+"""
+
+import subprocess
+import sys
+from pathlib import Path
+from typing import Any, Dict, List, Set
+
+CURRENT_DIR = Path(__file__).resolve().parent
+ROOT_DIR = CURRENT_DIR.parent.parent
+
+HELPER_FILE = ROOT_DIR / "core/src/apps/monero/xmr/crypto_helpers.py"
+MOCK_FILE = ROOT_DIR / "core/mocks/generated/trezorcrypto/monero.pyi"
+
+
+def generate_function_mapping() -> Dict[str, List[str]]:
+    """Look at all Monero functions and generate a mapping of their usage"""
+
+    # Load all the function names in .pyi file
+    pyi_functions: Set[str] = set()
+    with open(MOCK_FILE, "r") as f:
+        lines = f.readlines()
+        for line in lines:
+            if line.startswith("def"):
+                f_name = line.split("(")[0].split(" ")[1]
+                pyi_functions.add(f_name)
+
+    # Load definitions of helper functions
+    helper_func_defs: Dict[str, str] = {}
+    with open(HELPER_FILE, "r") as f:
+        lines = f.readlines()
+        current_func = ""
+        for line in lines:
+            if line.startswith("def"):
+                current_func = line.split("(")[0].split(" ")[1]
+                helper_func_defs[current_func] = line
+            elif not current_func:
+                continue
+            else:
+                helper_func_defs[current_func] += line
+
+    # Try to connect function names with helper definitions
+    func_mapping: Dict[str, List[str]] = {}
+    for func_name in pyi_functions:
+        func_mapping[func_name] = []
+        for func_def_name, func_code in helper_func_defs.items():
+            if f".{func_name}(" in func_code:
+                func_mapping[func_name].append(func_def_name)
+
+        # Functions may not be used in helper file, alias them to themselves
+        if not func_mapping[func_name]:
+            func_mapping[func_name] = [func_name]
+
+    return func_mapping
+
+
+def check_usage_of_functions(func_mapping: Dict[str, List[str]]) -> None:
+    """Go through all the functions and check if they are used in the Monero app.
+
+    Generates a report and exits with an appropriate exit code.
+    """
+
+    # Include boolean field to know what is used
+    is_used_mappings: Dict[str, Dict[str, Any]] = {}
+    for func_name, mapping in func_mapping.items():
+        is_used_mappings[func_name] = {"mapping": mapping, "is_used": False}
+
+    # Check if any of the mapping names is used - and mark it as used if so
+    for func_name in is_used_mappings:
+        for mapping in is_used_mappings[func_name]["mapping"]:
+            is_there = _is_used(mapping)
+            if is_there:
+                is_used_mappings[func_name]["is_used"] = True
+                break
+
+    # Find unused functions and generate a report
+    unused_functions = {
+        fc: val for fc, val in is_used_mappings.items() if not val["is_used"]
+    }
+    if not unused_functions:
+        print("SUCCESS: no functions are unused")
+        sys.exit(0)
+    else:
+        print(f"{len(unused_functions)} unused functions:")
+        for func, values in unused_functions.items():
+            print(func, values)
+        sys.exit(1)
+
+
+def _is_used(func_name: str) -> bool:
+    """Find function usage in the Monero app or in test files"""
+
+    cmds = [
+        rf'grep -r ".{func_name}\b" {ROOT_DIR}/core/src/apps/monero',
+        rf'grep -r ".{func_name}\b" {ROOT_DIR}/core/tests',
+    ]
+
+    for cmd in cmds:
+        grep_result = subprocess.run(cmd, shell=True, stdout=subprocess.PIPE)
+        if grep_result.returncode == 0:
+            return True
+
+    return False
+
+
+if "__main__" == __name__:
+    func_mapping = generate_function_mapping()
+    check_usage_of_functions(func_mapping)