Merge pull request swiftlang#2994 from Lukasa/cb-lifetime-management-in-nsstring

spevans · web-flow · commit 116823961282 · 2021-04-01T00:00:38.000+01:00
Cleanup lifetime management around NSData.bytes.
diff --git a/Sources/Foundation/Data.swift b/Sources/Foundation/Data.swift
@@ -2020,7 +2020,9 @@ public struct Data : ReferenceConvertible, Equatable, Hashable, RandomAccessColl
     @inlinable // This is @inlinable as a convenience initializer.
     public init(contentsOf url: __shared URL, options: Data.ReadingOptions = []) throws {
         let d = try NSData(contentsOf: url, options: ReadingOptions(rawValue: options.rawValue))
-        self.init(bytes: d.bytes, count: d.length)
+        self = withExtendedLifetime(d) {
+            return Data(bytes: d.bytes, count: d.length)
+        }
     }
     
     /// Initialize a `Data` from a Base-64 encoded String using the given options.
@@ -2031,7 +2033,9 @@ public struct Data : ReferenceConvertible, Equatable, Hashable, RandomAccessColl
     @inlinable // This is @inlinable as a convenience initializer.
     public init?(base64Encoded base64String: __shared String, options: Data.Base64DecodingOptions = []) {
         if let d = NSData(base64Encoded: base64String, options: Base64DecodingOptions(rawValue: options.rawValue)) {
-            self.init(bytes: d.bytes, count: d.length)
+            self = withExtendedLifetime(d) {
+                Data(bytes: d.bytes, count: d.length)
+            }
         } else {
             return nil
         }
@@ -2046,7 +2050,9 @@ public struct Data : ReferenceConvertible, Equatable, Hashable, RandomAccessColl
     @inlinable // This is @inlinable as a convenience initializer.
     public init?(base64Encoded base64Data: __shared Data, options: Data.Base64DecodingOptions = []) {
         if let d = NSData(base64Encoded: base64Data, options: Base64DecodingOptions(rawValue: options.rawValue)) {
-            self.init(bytes: d.bytes, count: d.length)
+            self = withExtendedLifetime(d) {
+                Data(bytes: d.bytes, count: d.length)
+            }
         } else {
             return nil
         }
diff --git a/Sources/Foundation/NSAttributedString.swift b/Sources/Foundation/NSAttributedString.swift
@@ -558,30 +558,31 @@ internal func _NSReadIntFromMutableAttributedStringCoding(_ data: NSData, _ star
     let length = data.length
     
     var value = 0
-    
-    while offset < length {
-        let i = Int(data.bytes.load(fromByteOffset: offset, as: UInt8.self))
-        
-        offset += 1
-        
-        let isLast = i < 128
-        
-        let intermediateValue = multiplier.multipliedReportingOverflow(by: isLast ? i : (i - 128))
-        guard !intermediateValue.overflow else { return nil }
-        
-        let newValue = value.addingReportingOverflow(intermediateValue.partialValue)
-        guard !newValue.overflow else { return nil }
-        
-        value = newValue.partialValue
 
-        if isLast {
-            return (value: value, newOffset: offset)
+    return withExtendedLifetime(data) { _ -> (Int, Int)? in
+        while offset < length {
+            let i = Int(data.bytes.load(fromByteOffset: offset, as: UInt8.self))
+
+            offset += 1
+
+            let isLast = i < 128
+
+            let intermediateValue = multiplier.multipliedReportingOverflow(by: isLast ? i : (i - 128))
+            guard !intermediateValue.overflow else { return nil }
+
+            let newValue = value.addingReportingOverflow(intermediateValue.partialValue)
+            guard !newValue.overflow else { return nil }
+
+            value = newValue.partialValue
+
+            if isLast {
+                return (value: value, newOffset: offset)
+            }
+
+            multiplier *= 128
         }
-        
-        multiplier *= 128
+        return nil // Getting to the end of the stream indicates error, since we were still expecting more bytes
     }
-    
-    return nil // Getting to the end of the stream indicates error, since we were still expecting more bytes
 }
 
 internal func _NSWriteIntToMutableAttributedStringCoding(_ i: Int, _ data: NSMutableData) {
diff --git a/Sources/Foundation/NSData.swift b/Sources/Foundation/NSData.swift
@@ -153,15 +153,20 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
     public init(contentsOfFile path: String, options readOptionsMask: ReadingOptions = []) throws {
         super.init()
         let readResult = try NSData.readBytesFromFileWithExtendedAttributes(path, options: readOptionsMask)
-        _init(bytes: readResult.bytes, length: readResult.length, copy: false, deallocator: readResult.deallocator)
+
+        withExtendedLifetime(readResult) {
+            _init(bytes: readResult.bytes, length: readResult.length, copy: false, deallocator: readResult.deallocator)
+        }
     }
 
     /// Initializes a data object with the contents of the file at a given path.
     public init?(contentsOfFile path: String) {
         do {
             super.init()
             let readResult = try NSData.readBytesFromFileWithExtendedAttributes(path, options: [])
-            _init(bytes: readResult.bytes, length: readResult.length, copy: false, deallocator: readResult.deallocator)
+            withExtendedLifetime(readResult) {
+                _init(bytes: readResult.bytes, length: readResult.length, copy: false, deallocator: readResult.deallocator)
+            }
         } catch {
             return nil
         }
@@ -179,15 +184,19 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
     public init(contentsOf url: URL, options readOptionsMask: ReadingOptions = []) throws {
         super.init()
         let (data, _) = try NSData.contentsOf(url: url, options: readOptionsMask)
-        _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+        withExtendedLifetime(data) {
+            _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+        }
     }
 
     /// Initializes a data object with the data from the location specified by a given URL.
     public init?(contentsOf url: URL) {
         super.init()
         do {
             let (data, _) = try NSData.contentsOf(url: url)
-            _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+            withExtendedLifetime(data) {
+                _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+            }
         } catch {
             return nil
         }
@@ -375,15 +384,19 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
             guard let data = aDecoder._decodePropertyListForKey("NS.data") as? NSData else {
                 return nil
             }
-            _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+            withExtendedLifetime(data) {
+                _init(bytes: UnsafeMutableRawPointer(mutating: data.bytes), length: data.length, copy: true)
+            }
         } else {
             let result : Data? = aDecoder.withDecodedUnsafeBufferPointer(forKey: "NS.bytes") {
                 guard let buffer = $0 else { return nil }
                 return Data(buffer: buffer)
             }
             
-            guard let r = result else { return nil }
-            _init(bytes: UnsafeMutableRawPointer(mutating: r._nsObject.bytes), length: r.count, copy: true)
+            guard var r = result else { return nil }
+            r.withUnsafeMutableBytes {
+                _init(bytes: $0.baseAddress, length: $0.count, copy: true)
+            }
         }
     }
     
@@ -559,24 +572,27 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
     /// Finds and returns the range of the first occurrence of the given data, within the given range, subject to given options.
     open func range(of dataToFind: Data, options mask: SearchOptions = [], in searchRange: NSRange) -> NSRange {
         let dataToFind = dataToFind._nsObject
-        guard dataToFind.length > 0 else {return NSRange(location: NSNotFound, length: 0)}
-        guard let searchRange = Range(searchRange) else {fatalError("invalid range")}
-        
-        precondition(searchRange.upperBound <= self.length, "range outside the bounds of data")
 
-        let basePtr = self.bytes.bindMemory(to: UInt8.self, capacity: self.length)
-        let baseData = UnsafeBufferPointer<UInt8>(start: basePtr, count: self.length)[searchRange]
-        let searchPtr = dataToFind.bytes.bindMemory(to: UInt8.self, capacity: dataToFind.length)
-        let search = UnsafeBufferPointer<UInt8>(start: searchPtr, count: dataToFind.length)
-        
-        let location : Int?
-        let anchored = mask.contains(.anchored)
-        if mask.contains(.backwards) {
-            location = NSData.searchSubSequence(search.reversed(), inSequence: baseData.reversed(),anchored : anchored).map {$0.base-search.count}
-        } else {
-            location = NSData.searchSubSequence(search, inSequence: baseData,anchored : anchored)
+        return withExtendedLifetime(dataToFind) {
+            guard dataToFind.length > 0 else {return NSRange(location: NSNotFound, length: 0)}
+            guard let searchRange = Range(searchRange) else {fatalError("invalid range")}
+
+            precondition(searchRange.upperBound <= self.length, "range outside the bounds of data")
+
+            let basePtr = self.bytes.bindMemory(to: UInt8.self, capacity: self.length)
+            let baseData = UnsafeBufferPointer<UInt8>(start: basePtr, count: self.length)[searchRange]
+            let searchPtr = dataToFind.bytes.bindMemory(to: UInt8.self, capacity: dataToFind.length)
+            let search = UnsafeBufferPointer<UInt8>(start: searchPtr, count: dataToFind.length)
+
+            let location : Int?
+            let anchored = mask.contains(.anchored)
+            if mask.contains(.backwards) {
+                location = NSData.searchSubSequence(search.reversed(), inSequence: baseData.reversed(),anchored : anchored).map {$0.base-search.count}
+            } else {
+                location = NSData.searchSubSequence(search, inSequence: baseData,anchored : anchored)
+            }
+            return location.map {NSRange(location: $0, length: search.count)} ?? NSRange(location: NSNotFound, length: 0)
         }
-        return location.map {NSRange(location: $0, length: search.count)} ?? NSRange(location: NSNotFound, length: 0)
     }
 
     private static func searchSubSequence<T : Collection, T2 : Sequence>(_ subSequence : T2, inSequence seq: T,anchored : Bool) -> T.Index? where T.Iterator.Element : Equatable, T.Iterator.Element == T2.Iterator.Element {
diff --git a/Sources/Foundation/NSString.swift b/Sources/Foundation/NSString.swift
@@ -1368,12 +1368,16 @@ extension NSString {
     public convenience init(contentsOf url: URL, encoding enc: UInt) throws {
         let readResult = try NSData(contentsOf: url, options: [])
 
-        let bytePtr = readResult.bytes.bindMemory(to: UInt8.self, capacity: readResult.length)
-        guard let cf = CFStringCreateWithBytes(kCFAllocatorDefault, bytePtr, readResult.length, CFStringConvertNSStringEncodingToEncoding(numericCast(enc)), true) else {
-            throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.fileReadInapplicableStringEncoding.rawValue, userInfo: [
-                NSDebugDescriptionErrorKey : "Unable to create a string using the specified encoding."
-                ])
+        let cf = try withExtendedLifetime(readResult) { _ -> CFString in
+            let bytePtr = readResult.bytes.bindMemory(to: UInt8.self, capacity: readResult.length)
+            guard let cf = CFStringCreateWithBytes(kCFAllocatorDefault, bytePtr, readResult.length, CFStringConvertNSStringEncodingToEncoding(numericCast(enc)), true) else {
+                throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.fileReadInapplicableStringEncoding.rawValue, userInfo: [
+                    NSDebugDescriptionErrorKey : "Unable to create a string using the specified encoding."
+                    ])
+            }
+            return cf
         }
+
         var str: String?
         if String._conditionallyBridgeFromObjectiveC(cf._nsObject, result: &str) {
             self.init(str!)
@@ -1391,44 +1395,49 @@ extension NSString {
     public convenience init(contentsOf url: URL, usedEncoding enc: UnsafeMutablePointer<UInt>?) throws {
         let (readResult, textEncodingNameMaybe) = try NSData.contentsOf(url: url)
 
-        let encoding: UInt
-        let offset: Int
-        // Look for a BOM (Byte Order Marker) to try and determine the text Encoding, this also skips
-        // over the bytes. This takes precedence over the textEncoding in the http header
-        let bytePtr = readResult.bytes.bindMemory(to: UInt8.self, capacity:readResult.length)
-        if readResult.length >= 4 && bytePtr[0] == 0xFF && bytePtr[1] == 0xFE && bytePtr[2] == 0x00 && bytePtr[3] == 0x00 {
-            encoding = String.Encoding.utf32LittleEndian.rawValue
-            offset = 4
-        }
-        else if readResult.length >= 2 && bytePtr[0] == 0xFE && bytePtr[1] == 0xFF {
-            encoding = String.Encoding.utf16BigEndian.rawValue
-            offset = 2
-        }
-        else if readResult.length >= 2 && bytePtr[0] == 0xFF && bytePtr[1] == 0xFE {
-            encoding = String.Encoding.utf16LittleEndian.rawValue
-            offset = 2
-        }
-        else if readResult.length >= 4 && bytePtr[0] == 0x00 && bytePtr[1] == 0x00 && bytePtr[2] == 0xFE && bytePtr[3] == 0xFF {
-            encoding = String.Encoding.utf32BigEndian.rawValue
-            offset = 4
-        }
-        else if let charSet = textEncodingNameMaybe, let textEncoding = String.Encoding(charSet: charSet) {
-            encoding = textEncoding.rawValue
-            offset = 0
-        } else {
-            //Need to work on more conditions. This should be the default
-            encoding = String.Encoding.utf8.rawValue
-            offset = 0
-        }
 
-        // Since the encoding being passed includes the byte order the BOM wont be checked or skipped, so pass offset to
-        // manually skip the BOM header.
-        guard let cf = CFStringCreateWithBytes(kCFAllocatorDefault, bytePtr + offset, readResult.length - offset,
-                                               CFStringConvertNSStringEncodingToEncoding(numericCast(encoding)), true) else {
-            throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.fileReadInapplicableStringEncoding.rawValue, userInfo: [
-                NSDebugDescriptionErrorKey : "Unable to create a string using the specified encoding."
-                ])
+        let (cf, encoding) = try withExtendedLifetime(readResult) { _ -> (CFString, UInt) in
+            let encoding: UInt
+            let offset: Int
+            // Look for a BOM (Byte Order Marker) to try and determine the text Encoding, this also skips
+            // over the bytes. This takes precedence over the textEncoding in the http header
+            let bytePtr = readResult.bytes.bindMemory(to: UInt8.self, capacity:readResult.length)
+            if readResult.length >= 4 && bytePtr[0] == 0xFF && bytePtr[1] == 0xFE && bytePtr[2] == 0x00 && bytePtr[3] == 0x00 {
+                encoding = String.Encoding.utf32LittleEndian.rawValue
+                offset = 4
+            }
+            else if readResult.length >= 2 && bytePtr[0] == 0xFE && bytePtr[1] == 0xFF {
+                encoding = String.Encoding.utf16BigEndian.rawValue
+                offset = 2
+            }
+            else if readResult.length >= 2 && bytePtr[0] == 0xFF && bytePtr[1] == 0xFE {
+                encoding = String.Encoding.utf16LittleEndian.rawValue
+                offset = 2
+            }
+            else if readResult.length >= 4 && bytePtr[0] == 0x00 && bytePtr[1] == 0x00 && bytePtr[2] == 0xFE && bytePtr[3] == 0xFF {
+                encoding = String.Encoding.utf32BigEndian.rawValue
+                offset = 4
+            }
+            else if let charSet = textEncodingNameMaybe, let textEncoding = String.Encoding(charSet: charSet) {
+                encoding = textEncoding.rawValue
+                offset = 0
+            } else {
+                //Need to work on more conditions. This should be the default
+                encoding = String.Encoding.utf8.rawValue
+                offset = 0
+            }
+
+            // Since the encoding being passed includes the byte order the BOM wont be checked or skipped, so pass offset to
+            // manually skip the BOM header.
+            guard let cf = CFStringCreateWithBytes(kCFAllocatorDefault, bytePtr + offset, readResult.length - offset,
+                                                   CFStringConvertNSStringEncodingToEncoding(numericCast(encoding)), true) else {
+                throw NSError(domain: NSCocoaErrorDomain, code: CocoaError.fileReadInapplicableStringEncoding.rawValue, userInfo: [
+                    NSDebugDescriptionErrorKey : "Unable to create a string using the specified encoding."
+                    ])
+            }
+            return (cf, encoding)
         }
+
         var str: String?
         if String._conditionallyBridgeFromObjectiveC(cf._nsObject, result: &str) {
             self.init(str!)
diff --git a/Sources/Foundation/NSTimeZone.swift b/Sources/Foundation/NSTimeZone.swift
@@ -95,7 +95,10 @@ open class NSTimeZone : NSObject, NSCopying, NSSecureCoding, NSCoding {
     
     public convenience init?(abbreviation: String) {
         let abbr = abbreviation._cfObject
-        guard let name = unsafeBitCast(CFDictionaryGetValue(CFTimeZoneCopyAbbreviationDictionary(), unsafeBitCast(abbr, to: UnsafeRawPointer.self)), to: NSString?.self) else {
+        let possibleName: NSString? = withExtendedLifetime(abbr) {
+            return unsafeBitCast(CFDictionaryGetValue(CFTimeZoneCopyAbbreviationDictionary(), unsafeBitCast(abbr, to: UnsafeRawPointer.self)), to: NSString?.self)
+        }
+        guard let name = possibleName else {
             return nil
         }
         self.init(name: name._swiftObject , data: nil)
diff --git a/Sources/FoundationNetworking/NSURLRequest.swift b/Sources/FoundationNetworking/NSURLRequest.swift
@@ -237,8 +237,10 @@ open class NSURLRequest : NSObject, NSSecureCoding, NSCopying, NSMutableCopying
         aCoder.encode(self.cachePolicy.rawValue._bridgeToObjectiveC(), forKey: "NS._cachePolicy")
         aCoder.encode(self.timeoutInterval._bridgeToObjectiveC(), forKey: "NS._timeoutInterval")
         if let httpBody = self.httpBody?._bridgeToObjectiveC() {
-            let bytePtr = httpBody.bytes.bindMemory(to: UInt8.self, capacity: httpBody.length)
-            aCoder.encodeBytes(bytePtr, length: httpBody.length, forKey: "NS.httpBody")
+            withExtendedLifetime(httpBody) {
+                let bytePtr = httpBody.bytes.bindMemory(to: UInt8.self, capacity: httpBody.length)
+                aCoder.encodeBytes(bytePtr, length: httpBody.length, forKey: "NS.httpBody")
+            }
         }
         //On macOS input stream is not encoded.
         aCoder.encode(self.networkServiceType.rawValue._bridgeToObjectiveC(), forKey: "NS._networkServiceType")
diff --git a/Sources/FoundationNetworking/URLSession/NativeProtocol.swift b/Sources/FoundationNetworking/URLSession/NativeProtocol.swift
@@ -256,7 +256,9 @@ internal class _NativeProtocol: URLProtocol, _EasyHandleDelegate {
         if case .inMemory(let bodyData) = bodyDataDrain {
             var data = Data()
             if let body = bodyData {
-                data = Data(bytes: body.bytes, count: body.length)
+                withExtendedLifetime(body) {
+                    data = Data(bytes: body.bytes, count: body.length)
+                }
             }
             self.client?.urlProtocol(self, didLoad: data)
             self.internalState = .taskCompleted
diff --git a/Sources/FoundationNetworking/URLSession/NetworkingSpecific.swift b/Sources/FoundationNetworking/URLSession/NetworkingSpecific.swift
@@ -85,7 +85,7 @@ class _NSNonfileURLContentLoader: _NSNonfileURLContentLoading {
             switch statusCode {
                 // These are the only valid response codes that data will be returned for, all other codes will be treated as error.
                 case 101, 200...399, 401, 407:
-                    return (NSData(bytes: UnsafeMutableRawPointer(mutating: (data as NSData).bytes), length: data.count), urlResponse?.textEncodingName)
+                    return (data as NSData, urlResponse?.textEncodingName)
 
                 default:
                     break
diff --git a/Tests/Foundation/Tests/TestNSArray.swift b/Tests/Foundation/Tests/TestNSArray.swift
diff --git a/Tests/Foundation/Tests/TestNSData.swift b/Tests/Foundation/Tests/TestNSData.swift
diff --git a/Tests/Foundation/Tests/TestXMLDocument.swift b/Tests/Foundation/Tests/TestXMLDocument.swift
