From 2a0c088fcdb60089f7cf93d1ab87db15ce0bb0d4 Mon Sep 17 00:00:00 2001
From: ShikiSuen <shikisuen@outlook.com>
Date: Sat, 22 Jan 2022 23:28:11 +0800
Subject: [PATCH] CNS // Phase 5: + MD5 check of the CSV data file.

---
 Source/LanguageModelManager.h  |  1 +
 Source/LanguageModelManager.mm | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/Source/LanguageModelManager.h b/Source/LanguageModelManager.h
index 78b541d1..0d7dbfc8 100644
--- a/Source/LanguageModelManager.h
+++ b/Source/LanguageModelManager.h
@@ -19,6 +19,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (void)loadDataModels;
 + (void)deployZipDataFile:(NSString *)filenameWithoutExtension;
 + (void)loadCNSData;
++ (BOOL)checkIfCNSDataExistAndHashMatched;
 + (void)loadUserPhrases;
 + (void)loadUserPhraseReplacement;
 + (BOOL)checkIfUserLanguageModelFilesExist;
diff --git a/Source/LanguageModelManager.mm b/Source/LanguageModelManager.mm
index e4480e56..a16a1891 100644
--- a/Source/LanguageModelManager.mm
+++ b/Source/LanguageModelManager.mm
@@ -64,6 +64,23 @@ static void LTLoadLanguageModelFile(NSString *filenameWithoutExtension, vChewing
     glanguageModelCoreCHS.loadCNSData([[self cnsDataPath] UTF8String]);
 }
 
++ (BOOL)checkIfCNSDataExistAndHashMatched
+{
+    if (![self checkIfUserDataFolderExists]) {
+        NSLog(@"User Data Folder N/A.");
+        return NO;
+    }
+    if (![self checkIfFileExist:[self cnsDataPath]]) {
+        NSLog(@"Extracted CNS Data Not Found.");
+        return NO;
+    }
+    if ([AWFileHash md5HashOfFileAtPath:[self cnsDataPath]] != [[NSUserDefaults standardUserDefaults] objectForKey:kMD5HashCNSData]) {
+        NSLog(@"Existing CNS CSV Data fingerprint mismatch, must be tampered since it gets extracted.");
+        return NO;
+    }
+    return YES;
+}
+
 + (void)loadUserPhrases
 {
     glanguageModelCoreCHT.loadUserPhrases([[self userPhrasesDataPath:kBopomofoModeIdentifierCHT] UTF8String], [[self excludedPhrasesDataPath:kBopomofoModeIdentifierCHT] UTF8String]);