[git log] Fix multi-value filter by user

Escaping baskslashes in 7eea76a introduced the problem with "\|"
separator used by Git to allow several users.

Backslashes should be escaped separately for text filter
and user filter: in the latter they should be escaped as well
(to allow a non-likely but possible case with backslash in user name)
before escaping "|".

platform/util/src/com/intellij/openapi/util/text/StringUtil.java

@@ -1720,7 +1720,7 @@ public class StringUtil extends StringUtilRt {
   }
 
   @NotNull
-  private static String escapeChar(@NotNull final String str, final char character) {
+  public static String escapeChar(@NotNull final String str, final char character) {
     final StringBuilder buf = new StringBuilder(str);
     escapeChar(buf, character);
     return buf.toString();

plugins/git4idea/src/git4idea/log/GitLogProvider.java

@@ -222,7 +222,7 @@ public class GitLogProvider implements VcsLogProvider {
           return filter.getUserName(root);
         }
       });
-      filterParameters.add(prepareParameter("author", authorFilter));
+      filterParameters.add(prepareParameter("author", StringUtil.escapeChar(StringUtil.escapeBackSlashes(authorFilter), '|')));
     }
 
     if (!dateFilters.isEmpty()) {
@@ -240,7 +240,7 @@ public class GitLogProvider implements VcsLogProvider {
       LOG.warn("Expected only one text filter: " + textFilters);
     }
     else if (!textFilters.isEmpty()) {
-      String textFilter = textFilters.iterator().next().getText();
+      String textFilter = StringUtil.escapeBackSlashes(textFilters.iterator().next().getText());
       filterParameters.add(prepareParameter("grep", textFilter));
     }
 
@@ -278,12 +278,11 @@ public class GitLogProvider implements VcsLogProvider {
   }
 
   private static String prepareParameter(String paramName, String value) {
-    // no value quoting needed, because the parameter itself will be quoted by GeneralCommandLine
-    return "--" + paramName + "=" + StringUtil.escapeBackSlashes(value);
+    return "--" + paramName + "=" + value; // no value quoting needed, because the parameter itself will be quoted by GeneralCommandLine
   }
 
   private static <T> String joinFilters(Collection<T> filters, Function<T, String> toString) {
-    return StringUtil.join(filters, toString, "\\|");
+    return StringUtil.join(filters, toString, "|");
   }
 
   @Nullable