From 161aa100cc292d5a90bc897f4b99d1a27a91eced Mon Sep 17 00:00:00 2001
From: ShikiSuen <shikisuen@outlook.com>
Date: Thu, 30 Nov 2023 20:39:56 +0800
Subject: [PATCH] LMAssembly // Correctly handle statement pointers.

---
 .../LangModelAssembly/LMInstantiator.swift    |  7 ---
 .../LMInstantiator_SQLExtension.swift         | 43 ++++++++++---------
 .../LangModelAssembly/vChewingLM.swift        | 26 ++++++++++-
 3 files changed, 47 insertions(+), 29 deletions(-)

diff --git a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift
index aad0d738..70c3b474 100644
--- a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift
+++ b/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
diff --git a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator_SQLExtension.swift b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator_SQLExtension.swift
index 9f6f6334..12e9a151 100644
--- a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator_SQLExtension.swift
+++ b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator_SQLExtension.swift
@@ -57,23 +57,25 @@ 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) }
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
-      guard let rawValue = sqlite3_column_text(Self.ptrStatement, column.id) else { continue }
-      handler(String(cString: rawValue))
+    performStatementSansResult { ptrStatement in
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
+        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) }
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
-      guard sqlite3_column_text(Self.ptrStatement, column.id) != nil else { continue }
-      return true
+    return performStatement { ptrStatement in
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
+        guard sqlite3_column_text(ptrStatement, column.id) != nil else { continue }
+        return true
+      }
+      return false
     }
-    return false
   }
 
   /// 获取字根反查资料。
@@ -81,15 +83,16 @@ extension vChewingLM.LMInstantiator {
     var results: [String] = []
     let sqlQuery = "SELECT * FROM DATA_REV WHERE theChar='\(kanji)';"
     guard Self.ptrSQL != nil else { return nil }
-    defer { sqlite3_finalize(Self.ptrStatement) }
-    sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &Self.ptrStatement, nil)
-    while sqlite3_step(Self.ptrStatement) == SQLITE_ROW {
-      guard let rawValue = sqlite3_column_text(Self.ptrStatement, 1) else { continue }
-      results.append(
-        contentsOf: String(cString: rawValue).split(separator: "\t").map { reading in
-          Self.restorePhonabetFromASCII(reading.description)
-        }
-      )
+    performStatementSansResult { ptrStatement in
+      sqlite3_prepare_v2(Self.ptrSQL, sqlQuery, -1, &ptrStatement, nil)
+      while sqlite3_step(ptrStatement) == SQLITE_ROW {
+        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
   }
diff --git a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/vChewingLM.swift b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/vChewingLM.swift
index ec8d4c07..801e3104 100644
--- a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/vChewingLM.swift
+++ b/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)
+}