From f56910db1efe25d2ce1d36db787c010a9f2a36f9 Mon Sep 17 00:00:00 2001
From: smizrahi <seb.mizrahi@gmail.com>
Date: Mon, 5 Feb 2024 10:50:07 +0100
Subject: [PATCH] fix(mail): Use text/plain fallback if an error occured while
 parsing html message

---
 .../UIxMailPartAlternativeViewer.m            | 24 ++++++-
 UI/MailPartViewers/UIxMailPartHTMLViewer.h    |  4 +-
 UI/MailPartViewers/UIxMailPartHTMLViewer.m    | 67 +++++++++++++++++++
 UI/MailPartViewers/UIxMailPartViewer.m        | 22 +++++-
 4 files changed, 112 insertions(+), 5 deletions(-)

diff --git a/UI/MailPartViewers/UIxMailPartAlternativeViewer.m b/UI/MailPartViewers/UIxMailPartAlternativeViewer.m
index 8b6a89f13..07185c8e4 100644
--- a/UI/MailPartViewers/UIxMailPartAlternativeViewer.m
+++ b/UI/MailPartViewers/UIxMailPartAlternativeViewer.m
@@ -179,8 +179,9 @@
   id info, viewer;
   NSArray *parts;
   NSMutableArray *renderedParts;
-  NSString *preferredType;
+  NSString *preferredType, *htmlNoTags;
   NSUInteger i, max;
+  BOOL fallbackNeeded, hasTextPlain;
 
   if ([self decodedFlatContent])
     parts = [[self decodedFlatContent] parts];
@@ -214,6 +215,27 @@
                             [[self childInfo] objectForKey: @"type"],
                             [[self childInfo] objectForKey: @"subtype"]];
 
+  // Check if the HTML part is good
+  // If no, try to fallback on text/plain
+  fallbackNeeded = NO;
+  hasTextPlain = NO;
+  for (i = 0 ; i < [renderedParts length] ; i++) {
+    if ([[[[renderedParts objectAtIndex: i] objectForKey: @"contentType"] lowercaseString] isEqualToString: @"text/html"]
+        && [[preferredType lowercaseString] isEqualToString: @"text/html"]) {
+      if ([[renderedParts objectAtIndex: i] objectForKey:@"exception"]) {
+        fallbackNeeded = YES;
+      }
+    }
+
+    if ([[[[renderedParts objectAtIndex: i] objectForKey: @"contentType"] lowercaseString] isEqualToString: @"text/plain"]) {
+      hasTextPlain = YES;
+    }
+  }
+
+  if (fallbackNeeded && hasTextPlain) {
+    preferredType = @"text/plain";
+  }
+
   return [NSDictionary dictionaryWithObjectsAndKeys:
                          [self className], @"type",
                        preferredType, @"preferredPart",
diff --git a/UI/MailPartViewers/UIxMailPartHTMLViewer.h b/UI/MailPartViewers/UIxMailPartHTMLViewer.h
index 5ba673c31..420ea75c7 100644
--- a/UI/MailPartViewers/UIxMailPartHTMLViewer.h
+++ b/UI/MailPartViewers/UIxMailPartHTMLViewer.h
@@ -23,9 +23,10 @@
 
 #import "UIxMailPartViewer.h"
 
-@interface UIxMailPartHTMLViewer : UIxMailPartViewer
+@interface UIxMailPartHTMLViewer : UIxMailPartViewer <SaxErrorHandler>
 {
   id handler;
+  NSException *ex;
 }
 
 - (NSString *) flatContentAsString;
@@ -35,6 +36,7 @@
 @interface UIxMailPartExternalHTMLViewer : UIxMailPartViewer
 {
   id handler;
+  NSException *ex;
 }
 
 - (NSString *) flatContentAsString;
diff --git a/UI/MailPartViewers/UIxMailPartHTMLViewer.m b/UI/MailPartViewers/UIxMailPartHTMLViewer.m
index b4eff9f03..a15c86522 100644
--- a/UI/MailPartViewers/UIxMailPartHTMLViewer.m
+++ b/UI/MailPartViewers/UIxMailPartHTMLViewer.m
@@ -750,6 +750,7 @@ _xmlCharsetForCharset (NSString *charset)
   if ((self = [super init]))
     {
       handler = nil;
+      ex = nil;
     }
 
   return self;
@@ -758,6 +759,9 @@ _xmlCharsetForCharset (NSString *charset)
 - (void) dealloc
 {
   [handler release];
+  if (ex) {
+    [ex release];
+  }
   [super dealloc];
 }
 
@@ -782,6 +786,8 @@ _xmlCharsetForCharset (NSString *charset)
 
   xmlCharEncoding enc;
 
+  [self cleanException];
+
   if ([[self decodedFlatContent] isKindOfClass: [NGMimeBodyPart class]])
     preparsedContent = [[[self decodedFlatContent] body] sanitizedContentUsingVoidTags: VoidTags];
   else
@@ -852,9 +858,37 @@ _xmlCharsetForCharset (NSString *charset)
   [handler setContentEncoding: enc];
 
   [parser setContentHandler: handler];
+  [parser setErrorHandler: self];
   [parser parseFromSource: preparsedContent];
 }
 
+- (void)cleanException
+{
+  ex = nil;
+}
+
+- (void)warning:(SaxParseException *)_exception
+{
+
+}
+
+- (void)error:(SaxParseException *)_exception
+{
+
+}
+
+- (void)fatalError:(SaxParseException *)_exception
+{
+  ex = [NSException exceptionWithName:[_exception name] reason: [_exception reason] userInfo: [_exception userInfo]];
+  [ex retain];
+}
+
+- (NSException *)getException
+{
+  return ex;
+}
+
+
 - (NSString *) cssContent
 {
   NSString *cssContent, *css;
@@ -890,6 +924,7 @@ _xmlCharsetForCharset (NSString *charset)
   if ((self = [super init]))
     {
       handler = nil;
+      ex = nil;
     }
 
   return self;
@@ -898,6 +933,9 @@ _xmlCharsetForCharset (NSString *charset)
 - (void) dealloc
 {
   [handler release];
+  if (ex) {
+    [ex release];
+  }
   [super dealloc];
 }
 
@@ -921,6 +959,8 @@ _xmlCharsetForCharset (NSString *charset)
   NSString *encoding;
   xmlCharEncoding enc;
 
+  [self cleanException];
+
   parser = [[SaxXMLReaderFactory standardXMLReaderFactory]
              createXMLReaderForMimeType: @"text/html"];
 
@@ -966,9 +1006,36 @@ _xmlCharsetForCharset (NSString *charset)
 
   [handler setContentEncoding: enc];
   [parser setContentHandler: handler];
+  [parser setErrorHandler: self];
   [parser parseFromSource: preparsedContent];
 }
 
+- (void)cleanException
+{
+  ex = nil;
+}
+
+- (void)warning:(SaxParseException *)_exception
+{
+
+}
+
+- (void)error:(SaxParseException *)_exception
+{
+
+}
+
+- (void)fatalError:(SaxParseException *)_exception
+{
+  ex = [NSException exceptionWithName:[_exception name] reason: [_exception reason] userInfo: [_exception userInfo]];
+  [ex retain];
+}
+
+- (NSException *)getException
+{
+  return ex;
+}
+
 - (NSString *) filename
 {
   return [[self clientObject] filename];
diff --git a/UI/MailPartViewers/UIxMailPartViewer.m b/UI/MailPartViewers/UIxMailPartViewer.m
index 13a7f89c9..7a2341c91 100644
--- a/UI/MailPartViewers/UIxMailPartViewer.m
+++ b/UI/MailPartViewers/UIxMailPartViewer.m
@@ -190,16 +190,27 @@
 
 - (id) renderedPart
 {
-  NSString *type;
+  NSString *type, *content;
+  NSException *e;
+  NSMutableDictionary *r;
 
+  e = nil;
   type = [NSString stringWithFormat: @"%@/%@",
                             [bodyInfo objectForKey: @"type"],
                             [bodyInfo objectForKey: @"subtype"]];
+  
 
-  return [NSDictionary dictionaryWithObjectsAndKeys:
+
+  content = [[[self generateResponse] contentAsString] stringWithoutHTMLInjection: NO];
+  if ([self respondsToSelector:@selector(getException)]) {
+    e = [self getException];
+  }
+  
+
+  r = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                          [self className], @"type",
                        type, @"contentType",
-                       [[[self generateResponse] contentAsString] stringWithoutHTMLInjection: NO], @"content",
+                       content, @"content",
                        [self filenameForDisplay], @"filename",
                        [self preferredPathExtension], @"extension",
                        [[self sizeFormatter] stringForObjectValue: [bodyInfo objectForKey: @"size"]], @"size",
@@ -207,6 +218,11 @@
                        [self pathForDownload], @"downloadURL",
                        [NSNumber numberWithBool:_shouldDisplayAttachment], @"shouldDisplayAttachment",
                        nil];
+  if (e) {
+    [r setObject: [e userInfo] forKey: @"exception"];
+  }
+  
+  return r;
 }
 
 - (NSDictionary *) attachmentIds