Accept newlines in link preview titles.

Signal/src/Models/CompareSafetyNumbersActivity.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -85,13 +85,13 @@ class CompareSafetyNumbersActivity: UIActivity {
     // MARK: Helpers
 
     func numericOnly(string: String?) -> String? {
-        guard (string != nil) else {
+        guard let string = string else {
             return nil
         }
 
         var numericOnly: String?
         if let regex = try? NSRegularExpression(pattern: "\\D", options: .caseInsensitive) {
-            numericOnly = regex.stringByReplacingMatches(in: string!, options: .withTransparentBounds, range: NSRange(location: 0, length: string!.count), withTemplate: "")
+            numericOnly = regex.stringByReplacingMatches(in: string, options: .withTransparentBounds, range: NSRange(location: 0, length: string.utf16.count), withTemplate: "")
         }
 
         return numericOnly

Signal/src/call/PeerConnectionClient.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -1107,12 +1107,12 @@ class HardenedRTCSessionDescription {
 
         // Enforce Constant bit rate.
         let cbrRegex = try! NSRegularExpression(pattern: "(a=fmtp:111 ((?!cbr=).)*)\r?\n", options: .caseInsensitive)
-        description = cbrRegex.stringByReplacingMatches(in: description, options: [], range: NSRange(location: 0, length: description.count), withTemplate: "$1;cbr=1\r\n")
+        description = cbrRegex.stringByReplacingMatches(in: description, options: [], range: NSRange(location: 0, length: description.utf16.count), withTemplate: "$1;cbr=1\r\n")
 
         // Strip plaintext audio-level details
         // https://tools.ietf.org/html/rfc6464
         let audioLevelRegex = try! NSRegularExpression(pattern: ".+urn:ietf:params:rtp-hdrext:ssrc-audio-level.*\r?\n", options: .caseInsensitive)
-        description = audioLevelRegex.stringByReplacingMatches(in: description, options: [], range: NSRange(location: 0, length: description.count), withTemplate: "")
+        description = audioLevelRegex.stringByReplacingMatches(in: description, options: [], range: NSRange(location: 0, length: description.utf16.count), withTemplate: "")
 
         return RTCSessionDescription.init(type: rtcSessionDescription.type, sdp: description)
     }
@@ -1161,7 +1161,7 @@ class HardenedRTCSessionDescription {
         do {
             let regex = try NSRegularExpression(pattern: "[\\da-f]*:[\\da-f]*:[\\da-f:\\.]*",
                 options: .caseInsensitive)
-            return regex.stringByReplacingMatches(in: sdp, options: [], range: NSRange(location: 0, length: sdp.count), withTemplate: "[ REDACTED_IPV6_ADDRESS ]")
+            return regex.stringByReplacingMatches(in: sdp, options: [], range: NSRange(location: 0, length: sdp.utf16.count), withTemplate: "[ REDACTED_IPV6_ADDRESS ]")
         } catch {
             owsFailDebug("Could not redact IPv6 addresses.")
             return "[Could not redact IPv6 addresses.]"

Signal/src/util/Backup/OWSBackupAPI.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -94,7 +94,7 @@ import PromiseKit
         var recipientIds = [String]()
         for recordName in recordNames {
             let regex = recordNamePrefixRegex
-            guard let match: NSTextCheckingResult = regex.firstMatch(in: recordName, options: [], range: NSRange(location: 0, length: recordName.count)) else {
+            guard let match: NSTextCheckingResult = regex.firstMatch(in: recordName, options: [], range: NSRange(location: 0, length: recordName.utf16.count)) else {
                 Logger.warn("no match: \(recordName)")
                 continue
             }

SignalServiceKit/src/Messages/Interactions/OWSLinkPreview.swift

@@ -751,7 +751,9 @@ public class OWSLinkPreview: MTLModel {
         }
 
         var title: String?
-        if let rawTitle = NSRegularExpression.parseFirstMatch(pattern: "<meta\\s+property\\s*=\\s*\"og:title\"\\s+content\\s*=\\s*\"(.*?)\"\\s*/?>", text: linkText) {
+        if let rawTitle = NSRegularExpression.parseFirstMatch(pattern: "<meta\\s+property\\s*=\\s*\"og:title\"\\s+content\\s*=\\s*\"(.*?)\"\\s*/?>",
+                                                              text: linkText,
+                                                              options: .dotMatchesLineSeparators) {
             if let decodedTitle = decodeHTMLEntities(inString: rawTitle) {
                 let normalizedTitle = OWSLinkPreview.normalizeTitle(title: decodedTitle)
                 if normalizedTitle.count > 0 {

SignalServiceKit/src/Util/NSRegularExpression+SSK.swift

@@ -14,12 +14,13 @@ public extension NSRegularExpression {
 
     @objc
     public class func parseFirstMatch(pattern: String,
-                                      text: String) -> String? {
+                                      text: String,
+                                      options: NSRegularExpression.Options = []) -> String? {
         do {
-            let regex = try NSRegularExpression(pattern: pattern)
+            let regex = try NSRegularExpression(pattern: pattern, options: options)
             guard let match = regex.firstMatch(in: text,
                                                options: [],
-                                               range: NSRange(location: 0, length: text.count)) else {
+                                               range: NSRange(location: 0, length: text.utf16.count)) else {
                                                 return nil
             }
             let matchRange = match.range(at: 1)

SignalServiceKit/tests/Messages/OWSLinkPreviewTest.swift

@@ -434,4 +434,24 @@ class OWSLinkPreviewTest: SSKBaseTestSwift {
 
         self.waitForExpectations(timeout: 5.0, handler: nil)
     }
+
+    // When using regular expressions to parse link titles, we need to use
+    // String.utf16.count, not String.count in the range.
+    func testRegexRanges() {
+        let regex = try! NSRegularExpression(pattern: "bob", options: [])
+        var text = "bob"
+        XCTAssertNotNil(regex.firstMatch(in: text,
+                                         options: [],
+                                         range: NSRange(location: 0, length: text.count)))
+        XCTAssertNotNil(regex.firstMatch(in: text,
+                                         options: [],
+                                         range: NSRange(location: 0, length: text.utf16.count)))
+        text = "😂😘🙂 bob"
+        XCTAssertNil(regex.firstMatch(in: text,
+                                         options: [],
+                                         range: NSRange(location: 0, length: text.count)))
+        XCTAssertNotNil(regex.firstMatch(in: text,
+                                         options: [],
+                                         range: NSRange(location: 0, length: text.utf16.count)))
+    }
 }