Simplify some while-loops

Author: nickdrozd

Lib/_pyio.py

@@ -651,10 +651,7 @@ def read(self, size=-1):
     def readall(self):
         """Read until EOF, using multiple read() call."""
         res = bytearray()
-        while True:
-            data = self.read(DEFAULT_BUFFER_SIZE)
-            if not data:
-                break
+        while (data := self.read(DEFAULT_BUFFER_SIZE)):
             res += data
         if res:
             return bytes(res)

Lib/aifc.py

@@ -954,9 +954,6 @@ def open(f, mode=None):
             print("Writing", gn)
             with open(gn, 'w') as g:
                 g.setparams(f.getparams())
-                while 1:
-                    data = f.readframes(1024)
-                    if not data:
-                        break
+                while (data := f.readframes(1024)):
                     g.writeframes(data)
             print("Done.")

Lib/base64.py

@@ -508,10 +508,7 @@ def b85decode(b):
 
 def encode(input, output):
     """Encode a file; input and output are binary files."""
-    while True:
-        s = input.read(MAXBINSIZE)
-        if not s:
-            break
+    while (s := input.read(MAXBINSIZE)):
         while len(s) < MAXBINSIZE:
             ns = input.read(MAXBINSIZE-len(s))
             if not ns:
@@ -523,10 +520,7 @@ def encode(input, output):
 
 def decode(input, output):
     """Decode a file; input and output are binary files."""
-    while True:
-        line = input.readline()
-        if not line:
-            break
+    while (line := input.readline()):
         s = binascii.a2b_base64(line)
         output.write(s)
 

Lib/ctypes/_aix.py

@@ -108,12 +108,8 @@ def get_ld_headers(file):
     p = Popen(["/usr/bin/dump", f"-X{AIX_ABI}", "-H", file],
         universal_newlines=True, stdout=PIPE, stderr=DEVNULL)
     # be sure to read to the end-of-file - getting all entries
-    while True:
-        ld_header = get_ld_header(p)
-        if ld_header:
-            ldr_headers.append((ld_header, get_ld_header_info(p)))
-        else:
-            break
+    while (ld_header := get_ld_header(p)):
+        ldr_headers.append((ld_header, get_ld_header_info(p)))
     p.stdout.close()
     p.wait()
     return ldr_headers

Lib/distutils/command/bdist_rpm.py

@@ -341,10 +341,7 @@ def run(self):
         try:
             binary_rpms = []
             source_rpm = None
-            while True:
-                line = out.readline()
-                if not line:
-                    break
+            while (line := out.readline()):
                 l = line.strip().split()
                 assert(len(l) == 2)
                 binary_rpms.append(l[1])

Lib/distutils/command/config.py

@@ -204,10 +204,7 @@ def search_cpp(self, pattern, body=None, headers=None, include_dirs=None,
 
         with open(out) as file:
             match = False
-            while True:
-                line = file.readline()
-                if line == '':
-                    break
+            while (line := file.readline()) != '':
                 if pattern.search(line):
                     match = True
                     break

Lib/distutils/command/sdist.py

@@ -333,11 +333,7 @@ def read_template(self):
                             collapse_join=1)
 
         try:
-            while True:
-                line = template.readline()
-                if line is None:            # end of file
-                    break
-
+            while (line := template.readline()) is not None:  # eof
                 try:
                     self.filelist.process_template_line(line)
                 # the call above can raise a DistutilsTemplateError for

Lib/distutils/extension.py

@@ -158,10 +158,7 @@ def read_setup_file(filename):
     try:
         extensions = []
 
-        while True:
-            line = file.readline()
-            if line is None:                # eof
-                break
+        while (line := file.readline()) is not None:  # eof
             if re.match(_variable_rx, line):    # VAR=VALUE, handled in first pass
                 continue
 

Lib/distutils/sysconfig.py

@@ -88,10 +88,7 @@ def parse_makefile(fn, g=None):
     done = {}
     notdone = {}
 
-    while True:
-        line = fp.readline()
-        if line is None: # eof
-            break
+    while (line := fp.readline()) is not None:  # eof
         m = re.match(_variable_rx, line)
         if m:
             n, v = m.group(1, 2)

Lib/distutils/text_file.py

@@ -273,11 +273,9 @@ def readlines(self):
         """Read and return the list of all logical lines remaining in the
            current file."""
         lines = []
-        while True:
-            line = self.readline()
-            if line is None:
-                return lines
+        while (line := self.readline()) is not None:
             lines.append(line)
+        return lines
 
     def unreadline(self, line):
         """Push 'line' (a string) onto an internal buffer that will be

Lib/email/parser.py

@@ -49,10 +49,7 @@ def parse(self, fp, headersonly=False):
         feedparser = FeedParser(self._class, policy=self.policy)
         if headersonly:
             feedparser._set_headersonly()
-        while True:
-            data = fp.read(8192)
-            if not data:
-                break
+        while (data := fp.read(8192)):
             feedparser.feed(data)
         return feedparser.close()
 

Lib/ftplib.py

@@ -434,10 +434,7 @@ def retrbinary(self, cmd, callback, blocksize=8192, rest=None):
         """
         self.voidcmd('TYPE I')
         with self.transfercmd(cmd, rest) as conn:
-            while 1:
-                data = conn.recv(blocksize)
-                if not data:
-                    break
+            while (data := conn.recv(blocksize)):
                 callback(data)
             # shutdown ssl layer
             if _SSLSocket is not None and isinstance(conn, _SSLSocket):
@@ -496,10 +493,7 @@ def storbinary(self, cmd, fp, blocksize=8192, callback=None, rest=None):
         """
         self.voidcmd('TYPE I')
         with self.transfercmd(cmd, rest) as conn:
-            while 1:
-                buf = fp.read(blocksize)
-                if not buf:
-                    break
+            while (buf := fp.read(blocksize)):
                 conn.sendall(buf)
                 if callback:
                     callback(buf)

Lib/http/client.py

@@ -578,11 +578,7 @@ def _read_chunked(self, amt=None):
         assert self.chunked != _UNKNOWN
         value = []
         try:
-            while True:
-                chunk_left = self._get_chunk_left()
-                if chunk_left is None:
-                    break
-
+            while (chunk_left := self._get_chunk_left()) is not None:
                 if amt is not None and amt <= chunk_left:
                     value.append(self._safe_read(amt))
                     self.chunk_left = chunk_left - amt
@@ -984,10 +980,7 @@ def send(self, data):
             encode = self._is_textIO(data)
             if encode and self.debuglevel > 0:
                 print("encoding file using iso-8859-1")
-            while 1:
-                datablock = data.read(self.blocksize)
-                if not datablock:
-                    break
+            while (datablock := data.read(self.blocksize)):
                 if encode:
                     datablock = datablock.encode("iso-8859-1")
                 sys.audit("http.client.send", self, datablock)
@@ -1017,10 +1010,7 @@ def _read_readable(self, readable):
         encode = self._is_textIO(readable)
         if encode and self.debuglevel > 0:
             print("encoding file using iso-8859-1")
-        while True:
-            datablock = readable.read(self.blocksize)
-            if not datablock:
-                break
+        while (datablock := readable.read(self.blocksize)):
             if encode:
                 datablock = datablock.encode("iso-8859-1")
             yield datablock

Lib/http/cookiejar.py

@@ -1920,9 +1920,7 @@ def _really_load(self, f, filename, ignore_discard, ignore_expires):
                        "comment", "commenturl")
 
         try:
-            while 1:
-                line = f.readline()
-                if line == "": break
+            while (line := f.readline()) != "":
                 if not line.startswith(header):
                     continue
                 line = line[len(header):].strip()
@@ -2022,12 +2020,9 @@ def _really_load(self, f, filename, ignore_discard, ignore_expires):
                 filename)
 
         try:
-            while 1:
-                line = f.readline()
+            while (line := f.readline()) != "":
                 rest = {}
 
-                if line == "": break
-
                 # httponly is a cookie flag as defined in rfc6265
                 # when encoded in a netscape cookie file,
                 # the line is prepended with "#HttpOnly_"

Lib/idlelib/idle_test/test_sidebar.py

@@ -474,10 +474,7 @@ def get_shell_line_y_coords(self):
         index = text.index("@0,0")
         if index.split('.', 1)[1] != '0':
             index = text.index(f"{index} +1line linestart")
-        while True:
-            lineinfo = text.dlineinfo(index)
-            if lineinfo is None:
-                break
+        while (lineinfo := text.dlineinfo(index)) is not None:
             y_coords.append(lineinfo[1])
             index = text.index(f"{index} +1line")
         return y_coords

Lib/idlelib/pyparse.py

@@ -179,14 +179,10 @@ def find_good_parse_start(self, is_char_in_string):
         # Peeking back worked; look forward until _synchre no longer
         # matches.
         i = pos + 1
-        while 1:
-            m = _synchre(code, i)
-            if m:
-                s, i = m.span()
-                if not is_char_in_string(s):
-                    pos = s
-            else:
-                break
+        while (m := _synchre(code, i)):
+            s, i = m.span()
+            if not is_char_in_string(s):
+                pos = s
         return pos
 
     def set_lo(self, lo):

Lib/idlelib/replace.py

@@ -158,11 +158,8 @@ def replace_all(self, event=None):
         first = last = None
         # XXX ought to replace circular instead of top-to-bottom when wrapping
         text.undo_block_start()
-        while True:
-            res = self.engine.search_forward(text, prog, line, col,
-                                             wrap=False, ok=ok)
-            if not res:
-                break
+        while (res := self.engine.search_forward(
+                text, prog, line, col, wrap=False, ok=ok)):
             line, m = res
             chars = text.get("%d.0" % line, "%d.0" % (line+1))
             orig = m.group()

Lib/idlelib/run.py

@@ -482,9 +482,7 @@ def read(self, size=-1):
         result = self._line_buffer
         self._line_buffer = ''
         if size < 0:
-            while True:
-                line = self.shell.readline()
-                if not line: break
+            while (line := self.shell.readline()):
                 result += line
         else:
             while len(result) < size:

Lib/idlelib/sidebar.py

@@ -471,10 +471,7 @@ def update_sidebar(self):
         index = text.index("@0,0")
         if index.split('.', 1)[1] != '0':
             index = text.index(f'{index}+1line linestart')
-        while True:
-            lineinfo = text.dlineinfo(index)
-            if lineinfo is None:
-                break
+        while (lineinfo := text.dlineinfo(index)) is not None:
             y = lineinfo[1]
             prev_newline_tagnames = text_tagnames(f"{index} linestart -1c")
             prompt = (

Lib/mailbox.py

@@ -1956,10 +1956,7 @@ def readlines(self, sizehint=None):
 
     def __iter__(self):
         """Iterate over lines."""
-        while True:
-            line = self.readline()
-            if not line:
-                return
+        while (line := self.readline()):
             yield line
 
     def tell(self):

Lib/mailcap.py

@@ -78,9 +78,7 @@ def _readmailcapfile(fp, lineno):
     the viewing command is stored with the key "view".
     """
     caps = {}
-    while 1:
-        line = fp.readline()
-        if not line: break
+    while (line := fp.readline()):
         # Ignore comments and blank lines
         if line[0] == '#' or line.strip() == '':
             continue

Lib/mimetypes.py

@@ -219,10 +219,7 @@ def readfp(self, fp, strict=True):
         list of standard types, else to the list of non-standard
         types.
         """
-        while 1:
-            line = fp.readline()
-            if not line:
-                break
+        while (line := fp.readline()):
             words = line.split()
             for i in range(len(words)):
                 if words[i][0] == '#':

Lib/pstats.py

@@ -223,8 +223,6 @@ def get_sort_arg_defs(self):
             for word, tup in self.sort_arg_dict_default.items():
                 fragment = word
                 while fragment:
-                    if not fragment:
-                        break
                     if fragment in dict:
                         bad_list[fragment] = 0
                         break

Lib/pydoc.py

@@ -679,9 +679,7 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}):
                                 r'RFC[- ]?(\d+)|'
                                 r'PEP[- ]?(\d+)|'
                                 r'(self\.)?(\w+))')
-        while True:
-            match = pattern.search(text, here)
-            if not match: break
+        while (match := pattern.search(text, here)):
             start, end = match.span()
             results.append(escape(text[here:start]))
 

Lib/quopri.py

@@ -67,10 +67,7 @@ def write(s, output=output, lineEnd=b'\n'):
             output.write(s + lineEnd)
 
     prevline = None
-    while 1:
-        line = input.readline()
-        if not line:
-            break
+    while (line := input.readline()):
         outline = []
         # Strip off any readline induced trailing newline
         stripped = b''
@@ -126,9 +123,7 @@ def decode(input, output, header=False):
         return
 
     new = b''
-    while 1:
-        line = input.readline()
-        if not line: break
+    while (line := input.readline()):
         i, n = 0, len(line)
         if n > 0 and line[n-1:n] == b'\n':
             partial = 0; n = n-1

Lib/shlex.py

@@ -335,10 +335,7 @@ def quote(s):
 
 
 def _print_tokens(lexer):
-    while 1:
-        tt = lexer.get_token()
-        if not tt:
-            break
+    while (tt := lexer.get_token()):
         print("Token: " + repr(tt))
 
 if __name__ == '__main__':