Split uos module into os and storage.

os is a subset of CPython's os. storage contains additional
file system mounting functionality based on UNIX's mount
management.

Fixes #140

1 files changed, 133 insertions, 0 deletions

diff --git a/shared-module/storage/__init__.c b/shared-module/storage/__init__.c
new file mode 100644
index 000000000..582b91a5b
--- /dev/null
+++ b/shared-module/storage/__init__.c
@@ -0,0 +1,133 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ * Copyright (c) 2015 Josef Gajdusek
+ * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "extmod/vfs.h"
+#include "py/mperrno.h"
+#include "py/obj.h"
+#include "py/runtime.h"
+#include "shared-bindings/storage/__init__.h"
+
+STATIC mp_obj_t mp_vfs_proxy_call(mp_vfs_mount_t *vfs, qstr meth_name, size_t n_args, const mp_obj_t *args) {
+    if (vfs == MP_VFS_NONE) {
+        // mount point not found
+        mp_raise_OSError(MP_ENODEV);
+    }
+    if (vfs == MP_VFS_ROOT) {
+        // can't do operation on root dir
+        mp_raise_OSError(MP_EPERM);
+    }
+    mp_obj_t meth[n_args + 2];
+    mp_load_method(vfs->obj, meth_name, meth);
+    if (args != NULL) {
+        memcpy(meth + 2, args, n_args * sizeof(*args));
+    }
+    return mp_call_method_n_kw(n_args, 0, meth);
+}
+
+void common_hal_storage_mount(mp_obj_t vfs_obj, const char* mount_path, bool readonly) {
+    // create new object
+    mp_vfs_mount_t *vfs = m_new_obj(mp_vfs_mount_t);
+    vfs->str = mount_path;
+    vfs->len = strlen(mount_path);
+    vfs->obj = vfs_obj;
+    vfs->next = NULL;
+
+    mp_obj_t args[2];
+    args[0] = readonly ? mp_const_true : mp_const_false;
+    args[1] = mp_const_false; // Don't make the file system automatically when mounting.
+
+    // call the underlying object to do any mounting operation
+    mp_vfs_proxy_call(vfs, MP_QSTR_mount, 2, (mp_obj_t*)&args);
+
+    // check that the destination mount point is unused
+    const char *path_out;
+    mp_vfs_mount_t *existing_mount = mp_vfs_lookup_path(mount_path, &path_out);
+    if (existing_mount != MP_VFS_NONE && existing_mount != MP_VFS_ROOT) {
+        if (vfs->len != 1 && existing_mount->len == 1) {
+            // if root dir is mounted, still allow to mount something within a subdir of root
+        } else {
+            // mount point in use
+            mp_raise_OSError(MP_EPERM);
+        }
+    }
+
+    // insert the vfs into the mount table
+    mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table);
+    while (*vfsp != NULL) {
+        if ((*vfsp)->len == 1) {
+            // make sure anything mounted at the root stays at the end of the list
+            vfs->next = *vfsp;
+            break;
+        }
+        vfsp = &(*vfsp)->next;
+    }
+    *vfsp = vfs;
+}
+
+void common_hal_storage_umount_object(mp_obj_t vfs_obj) {
+    // remove vfs from the mount table
+    mp_vfs_mount_t *vfs = NULL;
+    for (mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table); *vfsp != NULL; vfsp = &(*vfsp)->next) {
+        if ((*vfsp)->obj == vfs_obj) {
+            vfs = *vfsp;
+            *vfsp = (*vfsp)->next;
+            break;
+        }
+    }
+
+    if (vfs == NULL) {
+        mp_raise_OSError(MP_EINVAL);
+    }
+
+    // if we unmounted the current device then set current to root
+    if (MP_STATE_VM(vfs_cur) == vfs) {
+        MP_STATE_VM(vfs_cur) = MP_VFS_ROOT;
+    }
+
+    // call the underlying object to do any unmounting operation
+    mp_vfs_proxy_call(vfs, MP_QSTR_umount, 0, NULL);
+}
+
+void common_hal_storage_umount_path(const char* mount_path) {
+    // remove vfs from the mount table
+    mp_obj_t *vfs_obj = NULL;
+    for (mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table); *vfsp != NULL; vfsp = &(*vfsp)->next) {
+        if (strcmp(mount_path, (*vfsp)->str) == 0) {
+            vfs_obj = (*vfsp)->obj;
+            break;
+        }
+    }
+
+    if (vfs_obj == NULL) {
+        mp_raise_OSError(MP_EINVAL);
+    }
+
+    common_hal_storage_umount_object(vfs_obj);
+}