From cb719c9569a4e18421a45db3138742282fd63b99 Mon Sep 17 00:00:00 2001
From: Sebastian Willenborg <comawill@wlnbrg.de>
Date: Sun, 16 Nov 2014 18:07:34 +0100
Subject: [PATCH] New Feature: Limitation of loaded bytes to prevent hangs on
 large files

---
 .../GeneratePreviewForURL.m                   | 33 +++++++++++++++++++
 README.md                                     | 10 ++++++
 2 files changed, 43 insertions(+)

diff --git a/QuickLookStephenProject/GeneratePreviewForURL.m b/QuickLookStephenProject/GeneratePreviewForURL.m
index 0edfc74..b3147bd 100644
--- a/QuickLookStephenProject/GeneratePreviewForURL.m
+++ b/QuickLookStephenProject/GeneratePreviewForURL.m
@@ -6,6 +6,7 @@
 
 #import "QLSFileAttributes.h"
 
+#define DEFAULT_MAX_FILE_SIZE 1024 * 100
 
 // Generate a preview for the document with the given url
 OSStatus GeneratePreviewForURL(void *thisInterface,
@@ -40,6 +41,38 @@ OSStatus GeneratePreviewForURL(void *thisInterface,
       (NSString *)kQLPreviewPropertyHeightKey     : @800
     };
 
+    // Get size of current File
+    NSFileManager *man = [NSFileManager defaultManager];
+    NSURL *file_url = (__bridge NSURL *)(url);
+    NSDictionary *attrs = [man attributesOfItemAtPath: [file_url path] error: NULL];
+
+    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
+
+    // the plugin is running as com.apple.quicklook.satellite therefore we need to load our own settings
+    NSDictionary *defaults = [userDefaults persistentDomainForName:@"com.whomwah.quicklookstephen"];
+
+    long long maxFileSizeSetting = [[defaults valueForKey:@"maxFileSize"] longLongValue];
+    unsigned long long maxFileSize = DEFAULT_MAX_FILE_SIZE;
+    if(maxFileSizeSetting > 0) {
+      maxFileSize = maxFileSizeSetting;
+    }
+
+    // Display less data, if file is too big
+    if(attrs.fileSize > maxFileSize) {
+      NSFileHandle *myFile= [NSFileHandle fileHandleForReadingAtPath:[file_url path]];
+      if(!myFile) {
+        return noErr;
+      }
+      NSData *displayData = [myFile readDataOfLength:maxFileSize];
+      [myFile closeFile];
+
+      QLPreviewRequestSetDataRepresentation(
+          request,
+          (__bridge CFDataRef)displayData,
+          kUTTypePlainText,
+          (__bridge CFDictionaryRef)previewProperties);
+      return noErr;
+    }
     QLPreviewRequestSetURLRepresentation(
         request,
         url,
diff --git a/README.md b/README.md
index 6189679..7f99498 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,16 @@ Compliling the project yourself? Just copy the generated `QLStephen.qlgenerator`
 file into the relevant `QuickLook` folder (as above).
 
 
+## Settings
+
+### Maximum file size
+
+To keep quickview fast the priview is limited in its number of shown bytes.
+The default value is 100kB.
+
+	defaults write com.whomwah.quicklookstephen maxFileSize 102400
+
+
 ## Trouble?
 
 If you’ve installed the plugin, but don’t see any changes: