Escaping to like expressions. (#1469) / Proper escaping of paired spe…

…cial chars
JetBrains · Jul 18, 2022 · e926b0c · e926b0c
1 parent fd2aecf
commit e926b0c
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Showing 4 changed files with 29 additions and 5 deletions.
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt
@@ -147,9 +147,27 @@ data class LikePattern(
     companion object {
         fun ofLiteral(text: String, escapeChar: Char = '\\'): LikePattern {
             val likePatternSpecialChars = currentDialect.likePatternSpecialChars
+            val nextExpectedPatternQueue = arrayListOf<Char>()
+            var nextCharToEscape: Char? = null
             val escapedPattern = buildString {
                 text.forEach {
-                    if (it in likePatternSpecialChars || it == escapeChar){
+                    val shouldEscape = when (it) {
+                        escapeChar -> true
+                        in likePatternSpecialChars -> {
+                            likePatternSpecialChars[it]?.let { nextChar ->
+                                nextExpectedPatternQueue.add(nextChar)
+                                nextCharToEscape = nextChar
+                            }
+                            true
+                        }
+                        nextCharToEscape -> {
+                            nextExpectedPatternQueue.removeLast()
+                            nextCharToEscape = nextExpectedPatternQueue.lastOrNull()
+                            true
+                        }
+                        else -> false
+                    }
+                    if (shouldEscape){
                         append(escapeChar)
                     }
                     append(it)

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt
@@ -564,7 +564,7 @@ interface DatabaseDialect {
 
     val supportsOrderByNullsFirstLast: Boolean get() = false
 
-    val likePatternSpecialChars: String get() = "%_"
+    val likePatternSpecialChars: Map<Char, Char?> get() = defaultLikePatternSpecialChars
 
     /** Returns the name of the current database. */
     fun getDatabase(): String
@@ -634,6 +634,10 @@ interface DatabaseDialect {
             append(" CASCADE")
         }
     }
+
+    companion object {
+        private val defaultLikePatternSpecialChars = mapOf('%' to null, '_' to null)
+    }
 }
 
 /**

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/SQLServerDialect.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/SQLServerDialect.kt
@@ -214,10 +214,11 @@ open class SQLServerDialect : VendorDialect(dialectName, SQLServerDataTypeProvid
     }
 
     // https://docs.microsoft.com/en-us/sql/t-sql/language-elements/like-transact-sql?redirectedfrom=MSDN&view=sql-server-ver15#arguments
-    override val likePatternSpecialChars: String = "%_[]"
+    override val likePatternSpecialChars = sqlServerLikePatternSpecialChars
 
     companion object {
         /** SQLServer dialect name */
         const val dialectName: String = "sqlserver"
+        private val sqlServerLikePatternSpecialChars = mapOf('%' to null, '_' to null, '[' to ']')
     }
 }
diff --git a/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/LikeTests.kt b/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/LikeTests.kt
@@ -26,7 +26,8 @@ class LikeTests : DatabaseTestsBase() {
         withTables(t) {
             // Lets assume there are no special chars outside this range
             val escapeChar = '+'
-            val charRange = ('A'..'Z').toSet() + db.dialect.likePatternSpecialChars.toList()
+            val dialectSpecialChars = db.dialect.likePatternSpecialChars
+            val charRange = ('A'..'Z').toSet() + dialectSpecialChars.keys + dialectSpecialChars.values.filterNotNull()
 
             charRange.forEach { chr ->
                 t.insert {
@@ -37,7 +38,7 @@ class LikeTests : DatabaseTestsBase() {
             val specialChars = charRange.filter {
                 t.select { t.char like LikePattern("" + it, escapeChar = escapeChar) }.count() != 1L
             }
-            assertEquals(db.dialect.likePatternSpecialChars.toSet(), specialChars.toSet())
+            assertEquals(specialChars.toSet(), dialectSpecialChars.keys)
         }
     }