From 6d27ae5a10619ff420ff974790accfda7169edcb Mon Sep 17 00:00:00 2001
From: Zhengguo Yang <yangzhgg@gmail.com>
Date: Sun, 21 Mar 2021 11:22:33 +0800
Subject: [PATCH] [Enhance] Support unescape some invisible char in separator
 (#5524)

---
 .../org/apache/doris/analysis/Separator.java  | 47 ++++++++++++++++++-
 .../apache/doris/analysis/SeparatorTest.java  | 12 +++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/Separator.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/Separator.java
index efc61d9b1e..11404b524f 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/Separator.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/Separator.java
@@ -91,10 +91,55 @@ public class Separator implements ParseNode {
             }
             return writer.toString();
         } else {
-            return originStr;
+            return unescape(originStr);
         }
     }
 
+    // unescape some invisible string literal to char, such as "/t" to char '/t'
+    private static String unescape(String orig) {
+        StringBuffer sb = new StringBuffer();
+        boolean hadSlash = false;
+        for (int i = 0; i < orig.length(); i++) {
+            char ch = orig.charAt(i);
+            if (hadSlash) {
+                hadSlash = false;
+                switch (ch) {
+                    case '\\':
+                        sb.append('\\');
+                        break;
+                    case '\'':
+                        sb.append('\'');
+                        break;
+                    case '\"':
+                        sb.append('"');
+                        break;
+                    case 'r':
+                        sb.append('\r');
+                        break;
+                    case 't':
+                        sb.append('\t');
+                        break;
+                    case 'n':
+                        sb.append('\n');
+                        break;
+                    default :
+                        sb.append('\\').append(ch);
+                        break;
+                }
+                continue;
+            } else if (ch == '\\') {
+                if (i == orig.length() - 1) {
+                    sb.append(ch);
+                } else {
+                    hadSlash = true;
+                }
+                continue;
+            }
+            sb.append(ch);
+        }
+        return sb.toString();
+    }
+
     public String toSql() {
         StringBuilder sb = new StringBuilder();
         sb.append("'").append(oriSeparator).append("'");
diff --git a/fe/fe-core/src/test/java/org/apache/doris/analysis/SeparatorTest.java b/fe/fe-core/src/test/java/org/apache/doris/analysis/SeparatorTest.java
index e499cc1d78..5fd8e7bc54 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/analysis/SeparatorTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/analysis/SeparatorTest.java
@@ -31,6 +31,18 @@ public class SeparatorTest {
         Assert.assertEquals("'\t'", separator.toSql());
         Assert.assertEquals("\t", separator.getSeparator());
 
+        // \\t
+        separator = new Separator("\\t");
+        separator.analyze();
+        Assert.assertEquals("'\\t'", separator.toSql());
+        Assert.assertEquals("\t", separator.getSeparator());
+
+        // \\\\t
+        separator = new Separator("\\\\t");
+        separator.analyze();
+        Assert.assertEquals("'\\\\t'", separator.toSql());
+        Assert.assertEquals("\\t", separator.getSeparator());
+
         // \x01
         separator = new Separator("\\x01");
         separator.analyze();