Handle escaping literal hosts properly

KSURLComponents.m

@@ -317,9 +317,30 @@ - (NSString *)host;
 }
 - (void)setHost:(NSString *)host;
 {
+    NSRange startBracket = [host rangeOfString:@"[" options:NSAnchoredSearch];
+    if (startBracket.location != NSNotFound)
+    {
+        NSRange endBracket = [host rangeOfString:@"]" options:NSAnchoredSearch|NSBackwardsSearch];
+        if (endBracket.location != NSNotFound)
+        {
+            host = [host substringWithRange:NSMakeRange(startBracket.length, host.length - endBracket.length - startBracket.length)];
+
+            CFStringRef escaped = CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)host, NULL, CFSTR("@/?#"), kCFStringEncodingUTF8);
+            // @ must be escaped so as not to confuse as a username
+            // Don't escape : as it's within a host literal, and likely part of an IPv6 address
+            // / ? and # must be escaped so as not to indicate start of path, query or fragment
+
+            NSString *encoded = [NSString stringWithFormat:@"[%@]", escaped];
+
+            self.percentEncodedHost = encoded;
+            CFRelease(escaped);
+            return;
+        }
+    }
+
     CFStringRef escaped = CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)host, NULL, CFSTR("@:/?#"), kCFStringEncodingUTF8);
     // @ must be escaped so as not to confuse as a username
-    // Escaping : too to avoid confusion with port. NSURLComponents doesn't do so at present rdar://14387977
+    // : must be escaped too to avoid confusion with port
     // / ? and # must be escaped so as not to indicate start of path, query or fragment
 
     self.percentEncodedHost = (NSString *)escaped;

TestKSFileUtilities/TestKSURLComponents.m

@@ -239,6 +239,16 @@ - (void)testHostEscaping;
     [components release];
 }
 
+- (void)testLiteralHostEscaping;
+{
+    KSURLComponents *components = [[KSURLComponents alloc] init];
+
+    components.host = @"[!*'();:@&=+$,/?#[]]";
+    STAssertEqualObjects(components.percentEncodedHost, @"[!*'();:%40&=+$,%2F%3F%23%5B%5D]", @"Bracketing in [ ] indicates a literal host, which is allowed to contain : characters, e.g. for IPv6 addresses");
+
+    [components release];
+}
+
 - (void)testPathEscaping;
 {
     KSURLComponents *components = [[KSURLComponents alloc] init];