py: Pretend frozen files are stored under .frozen rather than the empty path.

This makes it clear when frozen modules are loaded as opposed to the empty path
which represents the current working directory. Furthermore, by splitting the two
apart this allows one to control in what order frozen modules are loaded.

This is a prerequisite for #56.

1 files changed, 12 insertions, 11 deletions

diff --git a/py/frozenmod.c b/py/frozenmod.c
index 1eaaf574a..782b437af 100644
--- a/py/frozenmod.c
+++ b/py/frozenmod.c
@@ -44,13 +44,13 @@ extern const uint32_t mp_frozen_str_sizes[];
 extern const char mp_frozen_str_content[];
 
 // On input, *len contains size of name, on output - size of content
-const char *mp_find_frozen_str(const char *str, size_t *len) {
+const char *mp_find_frozen_str(const char *str, size_t str_len, size_t *len) {
     const char *name = mp_frozen_str_names;
 
     size_t offset = 0;
     for (int i = 0; *name != 0; i++) {
         size_t l = strlen(name);
-        if (l == *len && !memcmp(str, name, l)) {
+        if (l == str_len && !memcmp(str, name, l)) {
             *len = mp_frozen_str_sizes[i];
             return mp_frozen_str_content + offset;
         }
@@ -60,16 +60,16 @@ const char *mp_find_frozen_str(const char *str, size_t *len) {
     return NULL;
 }
 
-STATIC mp_lexer_t *mp_lexer_frozen_str(const char *str, size_t len) {
-    size_t name_len = len;
-    const char *content = mp_find_frozen_str(str, &len);
+STATIC mp_lexer_t *mp_lexer_frozen_str(const char *str, size_t str_len) {
+    size_t file_len;
+    const char *content = mp_find_frozen_str(str, str_len, &file_len);
 
     if (content == NULL) {
         return NULL;
     }
 
-    qstr source = qstr_from_strn(str, name_len);
-    mp_lexer_t *lex = MICROPY_MODULE_FROZEN_LEXER(source, content, len, 0);
+    qstr source = qstr_from_strn(str, str_len);
+    mp_lexer_t *lex = MICROPY_MODULE_FROZEN_LEXER(source, content, file_len, 0);
     return lex;
 }
 
@@ -82,11 +82,11 @@ STATIC mp_lexer_t *mp_lexer_frozen_str(const char *str, size_t len) {
 extern const char mp_frozen_mpy_names[];
 extern const mp_raw_code_t *const mp_frozen_mpy_content[];
 
-STATIC const mp_raw_code_t *mp_find_frozen_mpy(const char *str, size_t len) {
+STATIC const mp_raw_code_t *mp_find_frozen_mpy(const char *str, size_t str_len) {
     const char *name = mp_frozen_mpy_names;
     for (size_t i = 0; *name != 0; i++) {
         size_t l = strlen(name);
-        if (l == len && !memcmp(str, name, l)) {
+        if (l == str_len && !memcmp(str, name, l)) {
             return mp_frozen_mpy_content[i];
         }
         name += l + 1;
@@ -136,15 +136,16 @@ mp_import_stat_t mp_frozen_stat(const char *str) {
 }
 
 int mp_find_frozen_module(const char *str, size_t len, void **data) {
+    // The +8/-8 account for the .frozen/ path prefix used on frozen modules.
     #if MICROPY_MODULE_FROZEN_STR
-    mp_lexer_t *lex = mp_lexer_frozen_str(str, len);
+    mp_lexer_t *lex = mp_lexer_frozen_str(str + 8, len - 8);
     if (lex != NULL) {
         *data = lex;
         return MP_FROZEN_STR;
     }
     #endif
     #if MICROPY_MODULE_FROZEN_MPY
-    const mp_raw_code_t *rc = mp_find_frozen_mpy(str, len);
+    const mp_raw_code_t *rc = mp_find_frozen_mpy(str + 8, len - 8);
     if (rc != NULL) {
         *data = (void*)rc;
         return MP_FROZEN_MPY;