ask for file overwrite on sd card (#269)

Author: stepansnigirev

src/apps/bip85.py

@@ -6,9 +6,9 @@
 from embit import bip85
 from gui.common import add_button, add_button_pair, align_button_pair
 from gui.decorators import on_release
-from gui.screens import Menu, NumericScreen, QRAlert, Alert
+from gui.screens import Menu, NumericScreen, QRAlert, Alert, Prompt
 from gui.screens.mnemonic import MnemonicScreen
-from helpers import SDCardFile
+import platform
 
 class QRWithSD(QRAlert):
     SAVE = 1
@@ -119,8 +119,14 @@ async def menu(self, show_screen):
                 fname = "bip85-%s-mnemonic-%d-%d.txt" % (
                     fgp, num_words, index
                 )
-                with SDCardFile(fname, "w") as f:
-                    f.write(mnemonic)
+                with platform.sdcard as sd:
+                    if sd.file_exists(fname):
+                        scr = Prompt("Overwrite?", message="File %s already exists on the SD card. Overwrite?" % fname)
+                        confirm = await show_screen(scr)
+                        if not confirm:
+                            return True
+                    with sd.open(fname, "w") as f:
+                        f.write(mnemonic)
                 await show_screen(
                     Alert(
                         title="Success",
@@ -169,8 +175,9 @@ async def menu(self, show_screen):
         )
         if action == QRWithSD.SAVE:
             fname = "bip85-%s-%s-%d.txt" % (fgp, file_suffix, index)
-            with SDCardFile(fname, "w") as f:
-                f.write(res)
+            with platform.sdcard as sd:
+                with sd.open(fname, "w") as f:
+                    f.write(res)
             await show_screen(
                 Alert(
                     title="Success",

src/apps/wallets/wallet.py

@@ -11,7 +11,7 @@
 from embit.transaction import SIGHASH
 from .screens import WalletScreen, WalletInfoScreen
 from .commands import DELETE, EDIT, MENU, INFO, EXPORT
-from gui.screens import Menu, QRAlert, Alert
+from gui.screens import Menu, QRAlert, Alert, Prompt
 import lvgl as lv
 
 class WalletError(AppError):
@@ -69,7 +69,7 @@ async def export_menu(self, show_screen):
             buttons = [
                 (None, "Export options"),
                 (1, "Show QR code"),
-                (2, "Save to SD card", platform.is_sd_present()),
+                (2, "Save to SD card", platform.sdcard.is_present),
             ]
             menuitem = await show_screen(Menu(buttons, last=(255, None), title="Export wallet %s" % self.name))
             desc = add_checksum(str(self.descriptor.branch(0)))
@@ -83,13 +83,16 @@ async def export_menu(self, show_screen):
                 await show_screen(QRAlert(title="Export wallet %s" % self.name, qr_width=450,
                         message="Scan this QR code with compatible software wallet", qr_message=json.dumps(obj)))
             elif menuitem == 2:
-                if not platform.is_sd_present():
+                if not platform.sdcard.is_present:
                     raise WalletError("SD card is not present")
-                platform.mount_sdcard()
-                fname = "/sd/%s.json" % self.name
-                with open(platform.fpath(fname), "w") as f:
-                    json.dump(obj, f)
-                platform.unmount_sdcard()
+                with platform.sdcard as sd:
+                    fname = "%s.json" % (self.name or "wallet")
+                    if sd.file_exists(fname):
+                        confirm = await show_screen(Prompt("Overwrite?", message="File %s already exists on the SD card. Overwrite?" % fname))
+                        if not confirm:
+                            return
+                    with sd.open(fname, "w") as f:
+                        json.dump(obj, f)
                 await show_screen(Alert("Success!", "Wallet descriptor is written to\n\n%s" % fname))
             else:
                 return

src/apps/xpubs/xpubs.py

@@ -1,11 +1,11 @@
 from app import BaseApp, AppError
-from gui.screens import Menu, DerivationScreen, NumericScreen, Alert, InputScreen
+from gui.screens import Menu, DerivationScreen, NumericScreen, Alert, InputScreen, Prompt
 from .screens import XPubScreen
 import json
 from binascii import hexlify
 from embit.liquid.networks import NETWORKS
 from embit import bip32
-from helpers import is_liquid, SDCardFile
+from helpers import is_liquid
 from io import BytesIO
 import platform
 from collections import OrderedDict
@@ -101,12 +101,13 @@ async def menu(self, show_screen, show_all=False):
         elif menuitem == 3:
             file_format = await self.save_menu(show_screen)
             if file_format:
-                filename = self.save_all_to_sd(file_format)
-                await show_screen(
-                    Alert("Saved!",
-                          "Public keys are saved to the file:\n\n%s" % filename,
-                          button_text="Close")
-                )
+                filename = await self.save_all_to_sd(file_format, self.account, show_screen)
+                if filename is not None:
+                    await show_screen(
+                        Alert("Saved!",
+                              "Public keys are saved to the file:\n\n%s" % filename,
+                              button_text="Close")
+                    )
         elif menuitem == 4:
             from_account = await show_screen(
                 NumericScreen(
@@ -137,9 +138,7 @@ async def menu(self, show_screen, show_all=False):
             return True
         return False
 
-    def save_all_to_sd(self, file_format, account=None):
-        if account is None:
-            account = self.account
+    async def save_all_to_sd(self, file_format, account, show_screen):
 
         fingerprint = hexlify(self.keystore.fingerprint).decode()
 
@@ -148,11 +147,16 @@ def save_all_to_sd(self, file_format, account=None):
             file_format, fingerprint, account, extension,
         )
 
-        if not platform.is_sd_present():
+        if not platform.sdcard.is_present:
             raise AppError("Please insert SD card")
 
-        with SDCardFile(filename, "w") as f:
-            self._dump_account(f, file_format, account)
+        with platform.sdcard as sd:
+            if sd.file_exists(filename):
+                confirm = await show_screen(Prompt("Overwrite?", message="File %s already exists on the SD card. Overwrite?" % filename))
+                if not confirm:
+                    return
+            with sd.open(filename, "w") as f:
+                self._dump_account(f, file_format, account)
 
         return filename
 
@@ -173,10 +177,15 @@ async def export_multiple_accounts_xpubs(
             filename = "%s-%s-%d-%d.txt" % (
                 file_format, fingerprint, from_account, to_account
             )
-            with SDCardFile(filename, "w") as f:
-                for account in range(from_account, to_account+1):
-                    self.show_loader(title="Exporting account %d..." % account)
-                    self._dump_account(f, file_format, account)
+            with platform.sdcard as sd:
+                if sd.file_exists(filename):
+                    confirm = await show_screen(Prompt("Overwrite?", message="File %s already exists on the SD card. Overwrite?" % filename))
+                    if not confirm:
+                        return
+                with sd.open(filename, "w") as f:
+                    for account in range(from_account, to_account+1):
+                        self.show_loader(title="Exporting account %d..." % account)
+                        self._dump_account(f, file_format, account)
             await show_screen(
                 Alert(
                     "Success!",
@@ -187,7 +196,7 @@ async def export_multiple_accounts_xpubs(
         else: # cc format - one file per account
             for account in range(from_account, to_account+1):
                 self.show_loader(title="Exporting account %d..." % account)
-                self.save_all_to_sd(file_format, account)
+                await self.save_all_to_sd(file_format, account, show_screen)
             await show_screen(
                 Alert(
                     "Success!",
@@ -290,8 +299,9 @@ async def show_xpub(self, derivation, show_screen):
             await self.create_wallet(derivation, canonical, prefix, ver, show_screen)
         elif res:
             filename = "%s-%s.txt" % (fingerprint, derivation[2:].replace("/", "-"))
-            with SDCardFile(filename, "w") as f:
-                f.write(res)
+            with platform.sdcard as sd:
+                with sd.open(filename, "w") as f:
+                    f.write(res)
             await show_screen(
                 Alert("Saved!",
                       "Extended public key is saved to the file:\n\n%s" % filename,

src/helpers.py

@@ -175,37 +175,3 @@ def read_write(fin, fout, chunk_size=32):
         total += fout.write(chunk)
     return total
 
-class SDCardFile:
-    """open file on SD card, mount card on enter, unmount on exit
-
-    Usage:
-
-    with SDCardFile("/sd/blah", "w") as f:
-        f.write("blah")
-    """
-    def __init__(self, filename, *args, **kwargs):
-        self._filename = filename
-        self._args = args
-        self._kwargs = kwargs
-        self.file = None
-
-    def mount(self):
-        platform.mount_sdcard()
-
-    def unmount(self):
-        platform.unmount_sdcard()
-
-    def __enter__(self):
-        self.mount()
-        self.file = open(
-            platform.fpath("/sd/" + self._filename),
-            *self._args, **self._kwargs
-        )
-        return self.file
-
-    def __exit__(self, exc_type, exc_value, traceback):
-        if self.file:
-            self.file.close()
-            self.file = None
-        self.unmount()
-

src/hosts/sd.py

@@ -28,9 +28,9 @@ def reset_and_mount(self):
             self.f.close()
             os.remove(self.fram)
             self.f = None
-        if not platform.is_sd_present:
+        if not platform.sdcard.is_present:
             raise HostError("SD card is not inserted")
-        platform.mount_sdcard()
+        platform.sdcard.mount()
 
     def copy(self, fin, fout):
         b = bytearray(100)
@@ -60,7 +60,7 @@ async def get_data(self, raw=False, chunk_timeout=0.1):
                     self.copy(fin, fout)
             self.f = open(self.fram,"rb")
         finally:
-            platform.unmount_sdcard()
+            platform.sdcard.unmount()
         return self.f
 
     def truncate(self, fname):
@@ -120,6 +120,13 @@ async def send_data(self, stream, *args, **kwargs):
         new_fname = self.completed_filename(self.sd_file)
         self.reset_and_mount()
         try:
+            if platform.file_exists(new_fname):
+                confirm = await self.manager.gui.prompt("Overwrite?",
+                    "File %s exists. Overwrite?" % new_fname.split("/")[-1]
+                )
+                if not confirm:
+                    platform.sdcard.unmount()
+                    return
             if isinstance(stream, str):
                 with open(stream, "rb") as fin:
                     with open(new_fname, "wb") as fout:
@@ -129,7 +136,7 @@ async def send_data(self, stream, *args, **kwargs):
                     self.copy(stream, fout)
                 stream.seek(0)
         finally:
-            platform.unmount_sdcard()
+            platform.sdcard.unmount()
         show_qr = await self.manager.gui.prompt("Success!", "\n\nProcessed request is saved to\n\n%s\n\nShow as QR code?" % new_fname.split("/")[-1])
         if show_qr:
             await self._show_qr(stream, *args, **kwargs)

src/keystore/ram.py

@@ -395,14 +395,17 @@ async def show_mnemonic(self):
                     msg = self.mnemonic
                 await self.show(QRAlert(title="Your mnemonic as QR code", message=msg, qr_message=qr_msg, transcribe=True))
             elif v == ExportMnemonicScreen.SD:
-                if not platform.is_sd_present:
+                if not platform.sdcard.is_present:
                     raise KeyStoreError("SD card is not present")
                 if await self.show(Prompt("Are you sure?", message="Your mnemonic will be saved as a simple plaintext file.\n\nAnyone with access to it will be able to read your key.\n\nContinue?")):
-                    platform.mount_sdcard()
-                    fname = "/sd/%s.txt" % self.mnemonic.split()[0]
-                    with open(platform.fpath(fname), "w") as f:
-                        f.write(self.mnemonic)
-                    platform.unmount_sdcard()
+                    with platform.sdcard as sd:
+                        fname = "%s.txt" % self.mnemonic.split()[0]
+                        if sd.file_exists(fname):
+                            confirm = await self.show(Prompt("Overwrite?", message="File %s already exists on the SD card. Overwrite?" % fname))
+                            if not confirm:
+                                return
+                        with sd.open(fname, "w") as f:
+                            f.write(self.mnemonic)
                     await self.show(Alert(title="Mnemonic is saved!", message="You mnemonic is saved in plaintext to\n\n%s\n\nPlease keep it safe." % fname))
             else:
                 return