[processing] Use a more unique separator for log file

Fixes #17704

Author: nyalldawson

python/plugins/processing/core/ProcessingLog.py

@@ -32,6 +32,8 @@
 from processing.core.ProcessingConfig import ProcessingConfig
 from qgis.PyQt.QtCore import QCoreApplication
 
+LOG_SEPARATOR = '|~|'
+
 
 class ProcessingLog:
 
@@ -55,8 +57,8 @@ def addToLog(msg):
             # added. To avoid it stopping the normal functioning of the
             # algorithm, we catch all errors, assuming that is better
             # to miss some log info than breaking the algorithm.
-            line = 'ALGORITHM|' + datetime.datetime.now().strftime(
-                ProcessingLog.DATE_FORMAT) + '|' \
+            line = 'ALGORITHM' + LOG_SEPARATOR + datetime.datetime.now().strftime(
+                ProcessingLog.DATE_FORMAT) + LOG_SEPARATOR \
                 + msg + '\n'
             with codecs.open(ProcessingLog.logFilename(), 'a',
                              encoding='utf-8') as logfile:
@@ -80,10 +82,14 @@ def getLogEntries():
             lines = f.readlines()
         for line in lines:
             line = line.strip('\n').strip()
-            tokens = line.split('|')
+            tokens = line.split(LOG_SEPARATOR)
+            if len(tokens) <= 1:
+                # try old format log separator
+                tokens = line.split('|')
+
             text = ''
             for i in range(2, len(tokens)):
-                text += tokens[i] + '|'
+                text += tokens[i] + LOG_SEPARATOR
             if line.startswith('ALGORITHM'):
                 entries.append(LogEntry(tokens[1], tokens[2]))
 
@@ -108,7 +114,7 @@ def saveLog(fileName):
         entries = ProcessingLog.getLogEntries()
         with codecs.open(fileName, 'w', encoding='utf-8') as f:
             for entry in entries:
-                f.write('ALGORITHM|%s|%s\n' % (entry.date, entry.text))
+                f.write('ALGORITHM{}{}{}{}\n'.format(LOG_SEPARATOR, entry.date, LOG_SEPARATORentry.text))
 
     @staticmethod
     def tr(string, context=''):