tools/mpremote: Add readline support to mount.

This significantly speeds up readline on files opened
directly from a mpremote mount.

Signed-off-by: Andrew Leech <[email protected]>

tools/mpremote/mpremote/transport_serial.py

@@ -380,13 +380,14 @@ def umount_local(self):
     "CMD_ILISTDIR_NEXT": 3,
     "CMD_OPEN": 4,
     "CMD_CLOSE": 5,
-    "CMD_READ": 6,
-    "CMD_WRITE": 7,
-    "CMD_SEEK": 8,
-    "CMD_REMOVE": 9,
-    "CMD_RENAME": 10,
-    "CMD_MKDIR": 11,
-    "CMD_RMDIR": 12,
+    "CMD_READLINE": 6,
+    "CMD_READ": 7,
+    "CMD_WRITE": 8,
+    "CMD_SEEK": 9,
+    "CMD_REMOVE": 10,
+    "CMD_RENAME": 11,
+    "CMD_MKDIR": 12,
+    "CMD_RMDIR": 13,
 }
 
 fs_hook_code = """\
@@ -562,12 +563,14 @@ def readinto(self, buf):
         return n
 
     def readline(self):
-        l = ''
-        while 1:
-            c = self.read(1)
-            l += c
-            if c == '\\n' or c == '':
-                return l
+        c = self.cmd
+        c.begin(CMD_READLINE)
+        c.wr_s8(self.fd)
+        n = c.rd_u32()
+        buf = bytearray(n)
+        c.rd_bytes(buf)
+        c.end()
+        return bytes(buf)
 
     def readlines(self):
         ls = []
@@ -854,6 +857,15 @@ def do_read(self):
         self.wr_bytes(buf)
         # self.log_cmd(f"read {fd} {n} -> {len(buf)}")
 
+    def do_readline(self):
+        fd = self.rd_s8()
+        buf = self.data_files[fd][0].readline()
+        self.wr_u32(len(buf))
+        if self.data_files[fd][1]:
+            buf = bytes(buf, "utf8")
+        self.wr_bytes(buf)
+        # self.log_cmd(f"readline {fd} -> {len(buf)}")
+
     def do_seek(self):
         fd = self.rd_s8()
         n = self.rd_s32()
@@ -927,6 +939,7 @@ def do_rmdir(self):
         fs_hook_cmds["CMD_OPEN"]: do_open,
         fs_hook_cmds["CMD_CLOSE"]: do_close,
         fs_hook_cmds["CMD_READ"]: do_read,
+        fs_hook_cmds["CMD_READLINE"]: do_readline,
         fs_hook_cmds["CMD_WRITE"]: do_write,
         fs_hook_cmds["CMD_SEEK"]: do_seek,
         fs_hook_cmds["CMD_REMOVE"]: do_remove,