fix: Throw on white space in percent encoded values in url_decode (#1…

…1749)

Summary:
Pull Request resolved: #11749

url_decode currently accepts white space in percent encoded values, e.g. url_decode('% 1') will
return the same results as url_decode('%01')

Presto Java throws an exception in these cases.  This change ensures that Velox does the same.

Note that according to the standard the two characters following the percent should be hex digits, so
this is consistent.

Reviewed By: spershin

Differential Revision: D66785876

fbshipit-source-id: 9d345e89deea71866116f439e1982975b86dcf7a

velox/functions/prestosql/URLFunctions.h

@@ -163,14 +163,15 @@ FOLLY_ALWAYS_INLINE char decodeByte(const char* p, const char* end) {
     char* endptr;
     auto val = strtol(buf, &endptr, 16);
 
-    if (endptr != buf + 2) {
-      VELOX_USER_FAIL("Illegal hex characters in escape (%) pattern: {}", buf);
-    }
-
-    if (val < 0) {
-      VELOX_USER_FAIL(
-          "Illegal hex characters in escape (%) pattern - negative value");
-    }
+    VELOX_USER_CHECK(
+        endptr == buf + 2 && !std::isspace(buf[0]) && !std::isspace(buf[1]),
+        "Illegal hex characters in escape (%) pattern: {}",
+        buf);
+
+    VELOX_USER_CHECK_GE(
+        val,
+        0,
+        "Illegal hex characters in escape (%) pattern - negative value");
 
     return val;
   } else {

velox/functions/prestosql/tests/URLFunctionsTest.cpp

@@ -649,6 +649,8 @@ TEST_F(URLFunctionsTest, urlDecode) {
   EXPECT_THROW(urlDecode("http%3A%2F%"), VeloxUserError);
   EXPECT_THROW(urlDecode("http%3A%2F%2H"), VeloxUserError);
   EXPECT_THROW(urlDecode("%-1"), VeloxUserError);
+  EXPECT_THROW(urlDecode("% 1"), VeloxUserError);
+  EXPECT_THROW(urlDecode("%1 "), VeloxUserError);
 }
 
 } // namespace