Improve onion request path loading efficiency

Session.xcodeproj/project.pbxproj

@@ -305,6 +305,7 @@
 		B8FF8DAF25C0D00F004D1F22 /* SessionUtilitiesKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = C3C2A679255388CC00C340D1 /* SessionUtilitiesKit.framework */; };
 		B8FF8E6225C10DA5004D1F22 /* GeoLite2-Country-Blocks-IPv4 in Resources */ = {isa = PBXBuildFile; fileRef = B8FF8E6125C10DA5004D1F22 /* GeoLite2-Country-Blocks-IPv4 */; };
 		B8FF8E7425C10FC3004D1F22 /* GeoLite2-Country-Locations-English in Resources */ = {isa = PBXBuildFile; fileRef = B8FF8E7325C10FC3004D1F22 /* GeoLite2-Country-Locations-English */; };
+		B8FF8EA625C11FEF004D1F22 /* IPv4.swift in Sources */ = {isa = PBXBuildFile; fileRef = B8FF8EA525C11FEF004D1F22 /* IPv4.swift */; };
 		B90418E6183E9DD40038554A /* DateUtil.m in Sources */ = {isa = PBXBuildFile; fileRef = B90418E5183E9DD40038554A /* DateUtil.m */; };
 		B9EB5ABD1884C002007CBB57 /* MessageUI.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B9EB5ABC1884C002007CBB57 /* MessageUI.framework */; };
 		C300A5B22554AF9800555489 /* VisibleMessage+Profile.swift in Sources */ = {isa = PBXBuildFile; fileRef = C300A5B12554AF9800555489 /* VisibleMessage+Profile.swift */; };
@@ -1347,6 +1348,7 @@
 		B8D8F1EF256621180092EF10 /* MessageSender+Convenience.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = "MessageSender+Convenience.swift"; path = "../../SignalUtilitiesKit/Messaging/Sending & Receiving/MessageSender+Convenience.swift"; sourceTree = "<group>"; };
 		B8FF8E6125C10DA5004D1F22 /* GeoLite2-Country-Blocks-IPv4 */ = {isa = PBXFileReference; lastKnownFileType = file.bplist; name = "GeoLite2-Country-Blocks-IPv4"; path = "Countries/GeoLite2-Country-Blocks-IPv4"; sourceTree = "<group>"; };
 		B8FF8E7325C10FC3004D1F22 /* GeoLite2-Country-Locations-English */ = {isa = PBXFileReference; lastKnownFileType = file.bplist; name = "GeoLite2-Country-Locations-English"; path = "Countries/GeoLite2-Country-Locations-English"; sourceTree = "<group>"; };
+		B8FF8EA525C11FEF004D1F22 /* IPv4.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IPv4.swift; sourceTree = "<group>"; };
 		B90418E4183E9DD40038554A /* DateUtil.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DateUtil.h; sourceTree = "<group>"; };
 		B90418E5183E9DD40038554A /* DateUtil.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DateUtil.m; sourceTree = "<group>"; };
 		B9EB5ABC1884C002007CBB57 /* MessageUI.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MessageUI.framework; path = System/Library/Frameworks/MessageUI.framework; sourceTree = SDKROOT; };
@@ -2264,6 +2266,7 @@
 			children = (
 				C33FDB68255A580F00E217F9 /* ContentProxy.swift */,
 				C3C2A5BC255385EE00C340D1 /* HTTP.swift */,
+				B8FF8EA525C11FEF004D1F22 /* IPv4.swift */,
 				C3C2A5D92553860B00C340D1 /* JSON.swift */,
 				C33FDAF2255A580500E217F9 /* ProxiedContentDownloader.swift */,
 				C352A3A42557B5F000338F3E /* TSRequest.h */,
@@ -4838,6 +4841,7 @@
 				B8856D23256F116B001CE70E /* Weak.swift in Sources */,
 				C32C5A48256DB8F0003C73A2 /* BuildConfiguration.swift in Sources */,
 				C300A60D2554B31900555489 /* Logging.swift in Sources */,
+				B8FF8EA625C11FEF004D1F22 /* IPv4.swift in Sources */,
 				C3D9E35525675EE10040E4F3 /* MIMETypeUtil.m in Sources */,
 				C3A7219A2558C1660043A11F /* AnyPromise+Conversion.swift in Sources */,
 				C300A6322554B6D100555489 /* NSDate+Timestamp.mm in Sources */,

Session/Utilities/IP2Country.swift

@@ -2,10 +2,18 @@
 final class IP2Country {
     var countryNamesCache: [String:String] = [:]
 
-    private lazy var ipv4Table: [String:[String]] = {
+    private static let workQueue = DispatchQueue(label: "IP2Country.workQueue", qos: .utility) // It's important that this is a serial queue
+    static var isInitialized = false
+    
+    // MARK: Tables
+    /// This table has two columns: the "network" column and the "registered_country_geoname_id" column. The network column contains the **lower** bound of an IP
+    /// range and the "registered_country_geoname_id" column contains the ID of the country corresponding to that range. We look up an IP by finding the first index in the
+    /// network column where the value is greater than the IP we're looking up (converted to an integer). The IP we're looking up must then be in the range **before** that
+    /// range.
+    private lazy var ipv4Table: [String:[Int]] = {
         let url = Bundle.main.url(forResource: "GeoLite2-Country-Blocks-IPv4", withExtension: nil)!
         let data = try! Data(contentsOf: url)
-        return try! NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as! [String:[String]]
+        return try! NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as! [String:[Int]]
     }()
     
     private lazy var countryNamesTable: [String:[String]] = {
@@ -14,10 +22,6 @@ final class IP2Country {
         return try! NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as! [String:[String]]
     }()
 
-    private static let workQueue = DispatchQueue(label: "IP2Country.workQueue", qos: .utility) // It's important that this is a serial queue
-
-    static var isInitialized = false
-
     // MARK: Lifecycle
     static let shared = IP2Country()
 
@@ -28,29 +32,17 @@ final class IP2Country {
     deinit {
         NotificationCenter.default.removeObserver(self)
     }
-
+    
     // MARK: Implementation
     private func cacheCountry(for ip: String) -> String {
-        var truncatedIP = ip
+        if let result = countryNamesCache[ip] { return result }
-        func getCountryInternal() -> String {
+        let ipAsInt = IPv4.toInt(ip)
-            if let country = countryNamesCache[ip] { return country }
+        guard let ipv4TableIndex = given(ipv4Table["network"]!.firstIndex(where: { $0 > ipAsInt }), { $0 - 1 }) else { return "Unknown Country" } // Relies on the array being sorted
-            if let ipv4TableIndex = ipv4Table["network"]!.firstIndex(where: { $0.starts(with: truncatedIP) }) {
+        let countryID = ipv4Table["registered_country_geoname_id"]![ipv4TableIndex]
-                let countryID = ipv4Table["registered_country_geoname_id"]![ipv4TableIndex]
+        guard let countryNamesTableIndex = countryNamesTable["geoname_id"]!.firstIndex(of: String(countryID)) else { return "Unknown Country" }
-                if let countryNamesTableIndex = countryNamesTable["geoname_id"]!.firstIndex(of: countryID) {
+        let result = countryNamesTable["country_name"]![countryNamesTableIndex]
-                    let country = countryNamesTable["country_name"]![countryNamesTableIndex]
+        countryNamesCache[ip] = result
-                    countryNamesCache[ip] = country
+        return result
-                    return country
-                }
-            }
-            if truncatedIP.contains(".") && !truncatedIP.hasSuffix(".") { // The fuzziest we want to go is xxx.x
-                truncatedIP.removeLast()
-                if truncatedIP.hasSuffix(".") { truncatedIP.removeLast() }
-                return getCountryInternal()
-            } else {
-                return "Unknown Country"
-            }
-        }
-        return getCountryInternal()
     }
 
     @objc func populateCacheIfNeededAsync() {

SessionUtilitiesKit/Networking/IPv4.swift

@@ -0,0 +1,12 @@
+
+public enum IPv4 {
+    
+    public static func toInt(_ ip: String) -> Int {
+        let octets: [Int] = ip.split(separator: ".").map { Int($0)! }
+        var result: Int = 0
+        for i in stride(from: 3, through: 0, by: -1) {
+            result += octets[ 3 - i ] << (i * 8)
+        }
+        return result
+    }
+}