Always read all available lines from stdout and stderr

Should produce faster output.

src/octoprint/util/pip.py

@@ -124,34 +124,34 @@ class PipCaller(object):
 		all_stderr = []
 		try:
 			while p.returncode is None:
-				line = p.stderr.readline(timeout=0.5)
-				if line:
-					line = self._convert_line(line)
-					self._log_stderr(line)
-					all_stderr.append(line)
+				lines = p.stderr.readlines(timeout=0.5)
+				if lines:
+					lines = self._convert_lines(lines)
+					self._log_stderr(*lines)
+					all_stderr += lines
 
-				line = p.stdout.readline(timeout=0.5)
-				if line:
-					line = self._convert_line(line)
-					self._log_stdout(line)
-					all_stdout.append(line)
+				lines = p.stdout.readlines(timeout=0.5)
+				if lines:
+					lines = self._convert_lines(lines)
+					self._log_stdout(*lines)
+					all_stdout += lines
 
 				p.commands[0].poll()
 
 		finally:
 			p.close()
 
-		stderr = p.stderr.text
-		if stderr:
-			split_lines = map(self._convert_line, stderr.split("\n"))
-			self._log_stderr(*split_lines)
-			all_stderr += split_lines
+		lines = p.stderr.readlines()
+		if lines:
+			lines = map(self._convert_line, lines)
+			self._log_stderr(*lines)
+			all_stderr += lines
 
-		stdout = p.stdout.text
-		if stdout:
-			split_lines = map(self._convert_line, stdout.split("\n"))
-			self._log_stdout(*split_lines)
-			all_stdout += split_lines
+		lines = p.stdout.readlines()
+		if lines:
+			lines = map(self._convert_line, lines)
+			self._log_stdout(*lines)
+			all_stdout += lines
 
 		return p.returncode, all_stdout, all_stderr
 
@@ -240,6 +240,10 @@ class PipCaller(object):
 	def _log_stderr(self, *lines):
 		self.on_log_stderr(*lines)
 
+	@staticmethod
+	def _convert_lines(lines):
+		return map(PipCaller._convert_line, lines)
+
 	@staticmethod
 	def _convert_line(line):
 		return to_unicode(_clean_ansi(line), errors="replace")