LMAssembly // Correctly handle statement pointers.

Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift

@@ -36,9 +36,6 @@ public extension vChewingLM {
     // SQLite 連線是否已經建立。
     public private(set) static var isSQLDBConnected: Bool = false
 
-    // SQLite Statement 專用的記憶體位置。
-    static var ptrStatement: OpaquePointer?
-
     // 在函式內部用以記錄狀態的開關。
     public var isCassetteEnabled = false
     public var isPhraseReplacementEnabled = false
@@ -63,10 +60,6 @@ public extension vChewingLM {
     }
 
     public static func disconnectSQLDB() {
-      if Self.ptrStatement != nil {
-        sqlite3_finalize(Self.ptrStatement)
-        Self.ptrStatement = nil
-      }
       if Self.ptrSQL != nil {
         sqlite3_close_v2(Self.ptrSQL)
         Self.ptrSQL = nil

Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator_SQLExtension.swift

@@ -57,40 +57,43 @@ enum CoreColumn: Int32 {
 extension vChewingLM.LMInstantiator {
   fileprivate static func querySQL(strStmt sqlQuery: String, coreColumn column: CoreColumn, handler: (String) -> Void) {
     guard Self.ptrSQL != nil else { return }
-    defer { sqlite3_finalize(Self.ptrStatement) }
+    performStatementSansResult { ptrStatement in
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
-      guard let rawValue = sqlite3_column_text(Self.ptrStatement, column.id) else { continue }
+        guard let rawValue = sqlite3_column_text(ptrStatement, column.id) else { continue }
         handler(String(cString: rawValue))
       }
     }
+  }
 
   fileprivate static func hasSQLResult(strStmt sqlQuery: String, coreColumn column: CoreColumn) -> Bool {
     guard Self.ptrSQL != nil else { return false }
-    defer { sqlite3_finalize(Self.ptrStatement) }
+    return performStatement { ptrStatement in
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
-      guard sqlite3_column_text(Self.ptrStatement, column.id) != nil else { continue }
+        guard sqlite3_column_text(ptrStatement, column.id) != nil else { continue }
         return true
       }
       return false
     }
+  }
 
   /// 获取字根反查资料。
   public static func getFactoryReverseLookupData(with kanji: String) -> [String]? {
     var results: [String] = []
     let sqlQuery = "SELECT * FROM DATA_REV WHERE theChar='\(kanji)';"
     guard Self.ptrSQL != nil else { return nil }
-    defer { sqlite3_finalize(Self.ptrStatement) }
+    performStatementSansResult { ptrStatement in
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
-      guard let rawValue = sqlite3_column_text(Self.ptrStatement, 1) else { continue }
+        guard let rawValue = sqlite3_column_text(ptrStatement, 1) else { continue }
         results.append(
           contentsOf: String(cString: rawValue).split(separator: "\t").map { reading in
             Self.restorePhonabetFromASCII(reading.description)
           }
         )
       }
+    }
     return results.isEmpty ? nil : results
   }
 

Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/vChewingLM.swift

@@ -34,9 +34,11 @@ extension String {
     ptrDB != nil && sqlite3_exec(ptrDB, self, nil, nil, nil) == SQLITE_OK
   }
 
-  @discardableResult func runAsSQLPreparedStep(dbPointer ptrDB: inout OpaquePointer?, stmtPtr ptrStmt: inout OpaquePointer?) -> Bool {
+  @discardableResult func runAsSQLPreparedStep(dbPointer ptrDB: inout OpaquePointer?) -> Bool {
     guard ptrDB != nil else { return false }
-    return sqlite3_prepare_v2(ptrDB, self, -1, &ptrStmt, nil) == SQLITE_OK && sqlite3_step(ptrStmt) == SQLITE_DONE
+    return performStatement { ptrStmt in
+      sqlite3_prepare_v2(ptrDB, self, -1, &ptrStmt, nil) == SQLITE_OK && sqlite3_step(ptrStmt) == SQLITE_DONE
+    }
   }
 }
 
@@ -60,3 +62,23 @@ extension Array where Element == String {
     return true
   }
 }
+
+// MARK: - Safe APIs for using SQLite Statements.
+
+func performStatement(_ handler: (inout OpaquePointer?) -> Bool) -> Bool {
+  var ptrStmt: OpaquePointer?
+  defer {
+    sqlite3_finalize(ptrStmt)
+    ptrStmt = nil
+  }
+  return handler(&ptrStmt)
+}
+
+func performStatementSansResult(_ handler: (inout OpaquePointer?) -> Void) {
+  var ptrStmt: OpaquePointer?
+  defer {
+    sqlite3_finalize(ptrStmt)
+    ptrStmt = nil
+  }
+  handler(&ptrStmt)
+}