src/third_party/blink/Tools/Scripts/webkitpy/common/system/outputtee.py

# Copyright (c) 2009, Google Inc. All rights reserved.
# Copyright (c) 2009 Apple Inc. All rights reserved.
#
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# modification, are permitted provided that the following conditions are
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# notice, this list of conditions and the following disclaimer.
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import codecs
import os
import sys


# Simple class to split output between multiple destinations
class Tee:
    def __init__(self, *files):
        self.files = files

    # Callers should pass an already encoded string for writing.
    def write(self, bytes):
        for file in self.files:
            file.write(bytes)


class OutputTee:
    def __init__(self):
        self._original_stdout = None
        self._original_stderr = None
        self._files_for_output = []

    def add_log(self, path):
        log_file = self._open_log_file(path)
        self._files_for_output.append(log_file)
        self._tee_outputs_to_files(self._files_for_output)
        return log_file

    def remove_log(self, log_file):
        self._files_for_output.remove(log_file)
        self._tee_outputs_to_files(self._files_for_output)
        log_file.close()

    @staticmethod
    def _open_log_file(log_path):
        (log_directory, log_name) = os.path.split(log_path)
        if log_directory and not os.path.exists(log_directory):
            os.makedirs(log_directory)
        return codecs.open(log_path, "a+", "utf-8")

    def _tee_outputs_to_files(self, files):
        if not self._original_stdout:
            self._original_stdout = sys.stdout
            self._original_stderr = sys.stderr
        if files and len(files):
            sys.stdout = Tee(self._original_stdout, *files)
            sys.stderr = Tee(self._original_stderr, *files)
        else:
            sys.stdout = self._original_stdout
            sys.stderr = self._original_stderr