aiorepl: Use blocking reads for raw REPL and raw paste.

Raw REPL mode is generally used as a command channel where all stdio
traffic is related directly to the raw commands and responses sent.

For this to work in aiorepl we need to ensure background tasks don't sent/
receive anything on stdio else the command channel will be corrupted.

The simplest way to achieve this is to make the raw commands blocking and
atomic rather than asyncio, assuming the user wont leave the device in raw
mode for too long at any one time.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

micropython/aiorepl/aiorepl.py

@@ -161,7 +161,7 @@ async def task(g=None, prompt="--> "):
                                 cmd = cmd[:-1]
                                 sys.stdout.write("\x08 \x08")
                     elif c == CHAR_CTRL_A:
-                        await raw_repl(s, g)
+                        raw_repl(sys.stdin, g)
                         break
                     elif c == CHAR_CTRL_B:
                         continue
@@ -239,7 +239,7 @@ async def task(g=None, prompt="--> "):
         micropython.kbd_intr(3)
 
 
-async def raw_paste(s, g, window=512):
+def raw_paste(s, window=512):
     sys.stdout.write("R\x01")  # supported
     sys.stdout.write(bytearray([window & 0xFF, window >> 8, 0x01]).decode())
     eof = False
@@ -248,7 +248,7 @@ async def raw_paste(s, g, window=512):
     file = b""
     while not eof:
         for idx in range(window):
-            b = await s.read(1)
+            b = s.read(1)
             c = ord(b)
             if c == CHAR_CTRL_C or c == CHAR_CTRL_D:
                 # end of file
@@ -267,7 +267,12 @@ async def raw_paste(s, g, window=512):
     return file
 
 
-async def raw_repl(s: asyncio.StreamReader, g: dict):
+def raw_repl(s, g: dict):
+    """
+    This function is blocking to prevent other
+    async tasks from writing to the stdio stream and
+    breaking the raw repl session.
+    """
     heading = "raw REPL; CTRL-B to exit\n"
     line = ""
     sys.stdout.write(heading)
@@ -276,7 +281,7 @@ async def raw_repl(s: asyncio.StreamReader, g: dict):
         line = ""
         sys.stdout.write(">")
         while True:
-            b = await s.read(1)
+            b = s.read(1)
             c = ord(b)
             if c == CHAR_CTRL_A:
                 rline = line
@@ -284,7 +289,7 @@ async def raw_repl(s: asyncio.StreamReader, g: dict):
 
                 if len(rline) == 2 and ord(rline[0]) == CHAR_CTRL_E:
                     if rline[1] == "A":
-                        line = await raw_paste(s, g)
+                        line = raw_paste(s)
                         break
                 else:
                     # reset raw REPL

micropython/aiorepl/manifest.py

@@ -1,5 +1,5 @@
 metadata(
-    version="0.2.0",
+    version="0.2.1",
     description="Provides an asynchronous REPL that can run concurrently with an asyncio, also allowing await expressions.",
 )