Replace the custom filepath cache with a Python dictionary

src/picologging/_picologging.cxx

@@ -94,10 +94,8 @@ static int
 picologging_clear(PyObject *module)
 {
     picologging_state *state = get_picologging_state(module);
-    if (state && state->g_filepathCache) {
-      delete state->g_filepathCache;
-      state->g_filepathCache = nullptr;
-
+    if (state) {
+      Py_XDECREF(state->g_filepathCache);
       Py_DECREF(state->g_const_CRITICAL);
       Py_DECREF(state->g_const_ERROR);
       Py_DECREF(state->g_const_WARNING);
@@ -156,7 +154,7 @@ PyMODINIT_FUNC PyInit__picologging(void)
 
   // Initialize module state
   picologging_state *state = get_picologging_state(m);
-  state->g_filepathCache = new FilepathCache();
+  state->g_filepathCache = PyDict_New();
   state->g_const_CRITICAL = PyUnicode_FromString("CRITICAL");
   state->g_const_ERROR = PyUnicode_FromString("ERROR");
   state->g_const_WARNING = PyUnicode_FromString("WARNING");

src/picologging/filepathcache.cxx

@@ -3,36 +3,27 @@
 
 namespace fs = std::filesystem;
 
-const FilepathCacheEntry& FilepathCache::lookup(PyObject* pathname){
-    /*
-     * Notes: A vector ended up being significantly faster than an unordered_map,
-     * even though an unordered_map should probably be used.
-     * TODO #3 : Cap vector size or decide on a better map type.
-     */
-    Py_hash_t hash = PyObject_Hash(pathname);
-    for (auto& entry : cache){
-        if (entry.first == hash){
-            return entry.second;
-        }
+PyObject* lookup(PyObject* cache, PyObject* pathname){
+    PyObject* result = PyDict_GetItem(cache, pathname);
+    if (result != NULL){
+        return result;
     }
-    FilepathCacheEntry* entry = new FilepathCacheEntry();
+
     fs::path fs_path = fs::path(PyUnicode_AsUTF8(pathname));
+    PyObject *filename = nullptr, *module = nullptr;
 #ifdef WIN32
     const wchar_t* filename_wchar = fs_path.filename().c_str();
     const wchar_t* modulename = fs_path.stem().c_str();
-    entry->filename = PyUnicode_FromWideChar(filename_wchar, wcslen(filename_wchar)),
-    entry->module = PyUnicode_FromWideChar(modulename, wcslen(modulename));
+    filename = PyUnicode_FromWideChar(filename_wchar, wcslen(filename_wchar)),
+    module = PyUnicode_FromWideChar(modulename, wcslen(modulename));
 #else
-    entry->filename = PyUnicode_FromString(fs_path.filename().c_str());
-    entry->module = PyUnicode_FromString(fs_path.stem().c_str());
+    filename = PyUnicode_FromString(fs_path.filename().c_str());
+    module = PyUnicode_FromString(fs_path.stem().c_str());
 #endif
-    cache.push_back({hash, *entry});
-    return *entry;
+    PyObject *cacheItem = PyTuple_Pack(2, filename, module);
+    PyDict_SetItem(cache, pathname, cacheItem);
+    Py_DECREF(cacheItem);
+    Py_DECREF(filename);
+    Py_DECREF(module);
+    return cacheItem;
 }
-
-FilepathCache::~FilepathCache(){
-    for (auto& entry : cache){
-        Py_CLEAR(entry.second.filename);
-        Py_CLEAR(entry.second.module);
-    }
-}

src/picologging/filepathcache.hxx

@@ -1,21 +1,9 @@
 #include <Python.h>
 #include <structmember.h>
 #include <cstddef>
-#include <vector>
 
 #ifndef PICOLOGGING_FILEPATHCACHE_H
 #define PICOLOGGING_FILEPATHCACHE_H
 
-typedef struct {
-    PyObject* filename;
-    PyObject* module;
-} FilepathCacheEntry;
-
-class FilepathCache {
-    std::vector<std::pair<Py_hash_t, FilepathCacheEntry>> cache;
-public:
-    const FilepathCacheEntry& lookup(PyObject* filepath);
-    ~FilepathCache();
-};
-
+PyObject* lookup(PyObject* cache, PyObject* pathname);
 #endif // PICOLOGGING_FILEPATHCACHE_H

src/picologging/logrecord.cxx

@@ -112,9 +112,9 @@ LogRecord* LogRecord_create(LogRecord* self, PyObject* name, PyObject* msg, PyOb
 
 #ifdef PICOLOGGING_CACHE_FILEPATH
     if (state && state->g_filepathCache != nullptr) {
-        auto filepath = state->g_filepathCache->lookup(pathname);
-        self->filename = Py_NewRef(filepath.filename);
-        self->module = Py_NewRef(filepath.module);
+        auto filepath = lookup(state->g_filepathCache, pathname);
+        self->filename = Py_NewRef(PyTuple_GET_ITEM(filepath, 0));
+        self->module = Py_NewRef(PyTuple_GET_ITEM(filepath, 1));
     } else {
         // Manual lookup - TODO Raise warning?
         fs::path fs_path = fs::path(PyUnicode_AsUTF8(pathname));

src/picologging/picologging.hxx

@@ -6,7 +6,7 @@
 #define PICOLOGGING_H
 
 typedef struct {
-  FilepathCache* g_filepathCache;
+  PyObject* g_filepathCache;
   PyObject* g_const_CRITICAL;
   PyObject* g_const_ERROR;
   PyObject* g_const_WARNING;