Issue #3080: Create find_module_path() subfunction

Python/import.c

@@ -1598,57 +1598,53 @@ static int case_ok(char *, Py_ssize_t, Py_ssize_t, const char *);
 static int find_init_module(char *); /* Forward */
 static struct filedescr importhookdescr = {"", "", IMP_HOOK};
 
-static struct filedescr*
-find_module_path_list(char *fullname, const char *name,
-                      PyObject *search_path_list, PyObject *path_hooks,
-                      PyObject *path_importer_cache,
+/* Get the path of a module: get its importer and call importer.find_module()
+   hook, or check if the module if a package (if path/__init__.py exists).
+
+    -1: error: a Python error occurred
+     0: ignore: an error occurred because of invalid data, but the error is not
+        important enough to be reported.
+     1: get path: module not found, but *buf contains its path
+     2: found: *p_fd is the file descriptor (IMP_HOOK or PKG_DIRECTORY)
+        and *buf is the path */
+
+static int
+find_module_path(char *fullname, const char *name, PyObject *path,
+                 PyObject *path_hooks, PyObject *path_importer_cache,
                  char *buf, size_t buflen,
-                      FILE **p_fp, PyObject **p_loader)
+                 PyObject **p_loader, struct filedescr **p_fd)
 {
-    Py_ssize_t i, npath;
-    size_t len, namelen;
-    struct filedescr *fdp = NULL;
-    char *filemode;
-    FILE *fp = NULL;
+    PyObject *path_bytes;
+    const char *base;
+    Py_ssize_t len;
+    size_t namelen;
     struct stat statbuf;
     static struct filedescr fd_package = {"", "", PKG_DIRECTORY};
-#if defined(PYOS_OS2)
-    size_t saved_len;
-    size_t saved_namelen;
-    char *saved_buf = NULL;
-#endif
 
-    npath = PyList_Size(search_path_list);
-    namelen = strlen(name);
-    for (i = 0; i < npath; i++) {
-        PyObject *v = PyList_GetItem(search_path_list, i);
-        PyObject *origv = v;
-        const char *base;
-        Py_ssize_t size;
-        if (!v)
-            return NULL;
-        if (PyUnicode_Check(v)) {
-            v = PyUnicode_EncodeFSDefault(v);
-            if (v == NULL)
-                return NULL;
+    if (PyUnicode_Check(path)) {
+        path_bytes = PyUnicode_EncodeFSDefault(path);
+        if (path_bytes == NULL)
+            return -1;
+    }
+    else if (PyBytes_Check(path)) {
+        Py_INCREF(path);
+        path_bytes = path;
     }
-        else if (!PyBytes_Check(v))
-            continue;
     else
-            Py_INCREF(v);
+        return 0;
 
-        base = PyBytes_AS_STRING(v);
-        size = PyBytes_GET_SIZE(v);
-        len = size;
+    namelen = strlen(name);
+    base = PyBytes_AS_STRING(path_bytes);
+    len = PyBytes_GET_SIZE(path_bytes);
     if (len + 2 + namelen + MAXSUFFIXSIZE >= buflen) {
-            Py_DECREF(v);
-            continue; /* Too long */
+        Py_DECREF(path_bytes);
+        return 0; /* Too long */
     }
     strcpy(buf, base);
-        Py_DECREF(v);
+    Py_DECREF(path_bytes);
 
     if (strlen(buf) != len) {
-            continue; /* v contains '\0' */
+        return 0; /* path_bytes contains '\0' */
     }
 
     /* sys.path_hooks import hook */
@@ -1656,9 +1652,9 @@ find_module_path_list(char *fullname, const char *name,
         PyObject *importer;
 
         importer = get_path_importer(path_importer_cache,
-                                         path_hooks, origv);
+                                     path_hooks, path);
         if (importer == NULL) {
-                return NULL;
+            return -1;
         }
         /* Note: importer is a borrowed reference */
         if (importer != Py_None) {
@@ -1667,14 +1663,15 @@ find_module_path_list(char *fullname, const char *name,
                                          "find_module",
                                          "s", fullname);
             if (loader == NULL)
-                    return NULL;  /* error */
+                return -1;  /* error */
             if (loader != Py_None) {
                 /* a loader was found */
                 *p_loader = loader;
-                    return &importhookdescr;
+                *p_fd = &importhookdescr;
+                return 2;
             }
             Py_DECREF(loader);
-                continue;
+            return 0;
         }
     }
     /* no hook was found, use builtin import */
@@ -1695,22 +1692,75 @@ find_module_path_list(char *fullname, const char *name,
         S_ISDIR(statbuf.st_mode) &&         /* it's a directory */
         case_ok(buf, len, namelen, name)) { /* case matches */
         if (find_init_module(buf)) { /* and has __init__.py */
-                return &fd_package;
+            *p_fd = &fd_package;
+            return 2;
         }
         else {
             int err;
             PyObject *unicode = PyUnicode_DecodeFSDefault(buf);
             if (unicode == NULL)
-                    return NULL;
+                return -1;
             err = PyErr_WarnFormat(PyExc_ImportWarning, 1,
                 "Not importing directory '%U': missing __init__.py",
                 unicode);
             Py_DECREF(unicode);
             if (err)
-                    return NULL;
+                return -1;
         }
     }
 #endif
+    return 1;
+}
+
+/* Find a module in search_path_list. For each path, try
+   find_module_filename() or try each _PyImport_Filetab suffix.
+
+   If the module is found, return a file descriptor, write the path in
+   *p_filename, write the pointer to the file object into *p_fp, and (if
+   p_loader is not NULL) the loader into *p_loader.
+
+   Otherwise, raise an exception and return NULL. */
+
+static struct filedescr*
+find_module_path_list(char *fullname, const char *name,
+                      PyObject *search_path_list, PyObject *path_hooks,
+                      PyObject *path_importer_cache,
+                      char *buf, size_t buflen,
+                      FILE **p_fp, PyObject **p_loader)
+{
+    Py_ssize_t i, npath;
+    size_t len, namelen;
+    struct filedescr *fdp = NULL;
+    char *filemode;
+    FILE *fp = NULL;
+#if defined(PYOS_OS2)
+    size_t saved_len;
+    size_t saved_namelen;
+    char *saved_buf = NULL;
+#endif
+
+    npath = PyList_Size(search_path_list);
+    namelen = strlen(name);
+    for (i = 0; i < npath; i++) {
+        PyObject *path;
+        int ok;
+
+        path = PyList_GetItem(search_path_list, i);
+        if (path == NULL)
+            return NULL;
+
+        ok = find_module_path(fullname, name, path,
+                              path_hooks, path_importer_cache,
+                              buf, buflen,
+                              p_loader, &fdp);
+        if (ok < 0)
+            return NULL;
+        if (ok == 0)
+            continue;
+        if (ok == 2)
+            return fdp;
+
+        len = strlen(buf);
 #if defined(PYOS_OS2)
         /* take a snapshot of the module spec for restoration
          * after the 8 character DLL hackery