404 lines
15 KiB
Swift
404 lines
15 KiB
Swift
//
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// Copyright 2024 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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import Foundation
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import SDWebImage
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public protocol OWSImageSource {
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var byteLength: Int { get }
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func readData(byteOffset: Int, byteLength: Int) throws -> Data
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func cgImageSource() throws -> CGImageSource?
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/// Potentially expensive, should be avoided if possible.
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func readIntoMemory() throws -> Data
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}
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extension Data: OWSImageSource {
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public var byteLength: Int { count }
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public func readData(byteOffset: Int, byteLength: Int) throws -> Data {
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return self[byteOffset..<(byteOffset + byteLength)]
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}
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public func cgImageSource() throws -> CGImageSource? {
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return CGImageSourceCreateWithData(self as CFData, nil)
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}
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public func readIntoMemory() throws -> Data {
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return self
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}
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}
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extension OWSImageSource {
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public var ows_isValidImage: Bool {
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return imageMetadata() != nil
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}
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public static func ows_isValidImage(at fileUrl: URL) -> Bool {
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return imageMetadata(withPath: fileUrl.path) != nil
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}
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public static func ows_isValidImage(atPath filePath: String) -> Bool {
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return imageMetadata(withPath: filePath) != nil
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}
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fileprivate static func ows_isValidImage(dimension imageSize: CGSize, depthBytes: CGFloat, isAnimated: Bool) -> Bool {
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if imageSize.width < 1 || imageSize.height < 1 || depthBytes < 1 {
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// Invalid metadata.
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return false
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}
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// We only support (A)RGB and (A)Grayscale, so worst case is 4.
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let worstCaseComponentsPerPixel = CGFloat(4)
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let bytesPerPixel = worstCaseComponentsPerPixel * depthBytes
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let expectedBytesPerPixel: CGFloat = 4
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let maxValidImageDimension: CGFloat = CGFloat(isAnimated ? OWSMediaUtils.kMaxAnimatedImageDimensions : OWSMediaUtils.kMaxStillImageDimensions)
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let maxBytes = maxValidImageDimension * maxValidImageDimension * expectedBytesPerPixel
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let actualBytes = imageSize.width * imageSize.height * bytesPerPixel
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if actualBytes > maxBytes {
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Logger.warn("invalid dimensions width: \(imageSize.width), height \(imageSize.height), bytesPerPixel: \(bytesPerPixel)")
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return false
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}
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return true
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}
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fileprivate func ows_guessHighEfficiencyImageFormat() -> ImageFormat? {
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// A HEIF image file has the first 16 bytes like
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// 0000 0018 6674 7970 6865 6963 0000 0000
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// so in this case the 5th to 12th bytes shall make a string of "ftypheic"
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let heifHeaderStartsAt = 4
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let heifBrandStartsAt = 8
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// We support "heic", "mif1" or "msf1". Other brands are invalid for us for now.
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// The length is 4 + 1 because the brand must be terminated with a null.
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// Include the null in the comparison to prevent a bogus brand like "heicfake"
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// from being considered valid.
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let heifSupportedBrandLength = 5
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let totalHeaderLength = heifBrandStartsAt - heifHeaderStartsAt + heifSupportedBrandLength
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guard byteLength >= heifBrandStartsAt + heifSupportedBrandLength else {
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return nil
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}
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// These are the brands of HEIF formatted files that are renderable by CoreGraphics
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let heifBrandHeaderHeic = Data("ftypheic\0".utf8)
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let heifBrandHeaderHeif = Data("ftypmif1\0".utf8)
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let heifBrandHeaderHeifStream = Data("ftypmsf1\0".utf8)
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// Pull the string from the header and compare it with the supported formats
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let header = try? readData(byteOffset: heifHeaderStartsAt, byteLength: totalHeaderLength)
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if header == heifBrandHeaderHeic {
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return .heic
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} else if header == heifBrandHeaderHeif || header == heifBrandHeaderHeifStream {
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return .heif
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} else {
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return nil
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}
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}
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fileprivate func ows_guessImageFormat() -> ImageFormat? {
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guard byteLength >= 2 else {
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return nil
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}
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switch try? readData(byteOffset: 0, byteLength: 2) {
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case Data([0x47, 0x49]):
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return .gif
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case Data([0x89, 0x50]):
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return .png
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case Data([0xff, 0xd8]):
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return .jpeg
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case Data([0x42, 0x4d]):
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return .bmp
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case Data([0x4d, 0x4d]), // Motorola byte order TIFF
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Data([0x49, 0x49]): // Intel byte order TIFF
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return .tiff
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case Data([0x52, 0x49]):
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// First two letters of RIFF tag.
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return .webp
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default:
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return ows_guessHighEfficiencyImageFormat()
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}
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}
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fileprivate static func applyImageOrientation(_ orientation: CGImagePropertyOrientation, to imageSize: CGSize) -> CGSize {
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// NOTE: UIImageOrientation and CGImagePropertyOrientation values
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// DO NOT match.
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switch orientation {
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case .up, .upMirrored, .down, .downMirrored:
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return imageSize
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case .left, .leftMirrored, .right, .rightMirrored:
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return CGSize(width: imageSize.height, height: imageSize.width)
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}
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}
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public static func hasAlpha(forValidImageFilePath filePath: String) -> Bool {
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if isWebp(filePath: filePath) {
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return true
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}
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let url = URL(fileURLWithPath: filePath)
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// With CGImageSource we avoid loading the whole image into memory.
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guard let _ = CGImageSourceCreateWithURL(url as CFURL, nil) else {
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owsFailDebug("Could not load image: \(url)")
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return false
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}
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return imageMetadata(withPath: filePath)?.hasAlpha ?? false
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}
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/// Returns the image size in pixels.
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///
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/// Returns CGSizeZero on error.
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public static func imageSize(forFilePath filePath: String) -> CGSize {
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let imageMetadata = imageMetadata(withPath: filePath)
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return imageMetadata?.pixelSize ?? .zero
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}
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/// Determine whether something is an animated PNG.
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///
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/// Does this by checking that the `acTL` chunk appears before any `IDAT` chunk.
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/// See [the APNG spec][0] for more.
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///
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/// [0]: https://wiki.mozilla.org/APNG_Specification
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///
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/// - Returns:
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/// `true` if the contents appear to be an APNG.
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/// `false` if the contents are a still PNG.
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/// `nil` if the contents are invalid.
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func isAnimatedPngData() -> NSNumber? {
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let actl = "acTL".data(using: .ascii)
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let idat = "IDAT".data(using: .ascii)
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do {
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let chunker = try PngChunker(source: self)
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while let chunk = try chunker.next() {
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if chunk.type == actl {
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return NSNumber(value: true)
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} else if chunk.type == idat {
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return NSNumber(value: false)
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}
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}
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} catch {
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Logger.warn("Error: \(error)")
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}
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return nil
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}
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// MARK: - Image Metadata
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public static func imageMetadata(withPath filePath: String, ignoreFileSize: Bool = false) -> ImageMetadata? {
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do {
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let data = try Data(contentsOf: URL(fileURLWithPath: filePath), options: .mappedIfSafe)
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// Use memory-mapped NSData instead of a URL-based
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// CGImageSource. We should usually only be reading
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// from (a small portion of) the file header,
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// depending on the file format.
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return data.imageMetadata(ignoreFileSize: ignoreFileSize)
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} catch {
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Logger.warn("Could not read image data: \(error)")
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return nil
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}
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}
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/// load image metadata about the current object
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public func imageMetadata(ignoreFileSize: Bool = false) -> ImageMetadata? {
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let result = _imageMetadataResult(ignorePerTypeFileSizeLimits: ignoreFileSize)
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switch result {
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case .invalid:
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return nil
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case .valid(let imageMetadata):
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return imageMetadata
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case .genericSizeLimitExceeded:
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return nil
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case .imageTypeSizeLimitExceeded:
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return nil
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}
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}
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/// Load image metadata about the current Data object.
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/// Returns nil if metadata could not be determined.
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public func imageMetadataResult() -> ImageMetadataResult {
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return _imageMetadataResult(ignorePerTypeFileSizeLimits: false)
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}
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private func _imageMetadataResult(ignorePerTypeFileSizeLimits: Bool) -> ImageMetadataResult {
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guard byteLength < OWSMediaUtils.kMaxFileSizeGeneric else {
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return .genericSizeLimitExceeded
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}
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let imageFormat = ows_guessImageFormat()
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guard let imageFormat else {
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Logger.warn("Image does not have valid format.")
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return .invalid
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}
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let isAnimated: Bool
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switch imageFormat {
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case .gif:
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// TODO: We currently treat all GIFs as animated. We could reflect the actual image content.
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isAnimated = true
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case .webp:
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let webpMetadata = metadataForWebp
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guard webpMetadata.isValid else {
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Logger.warn("Image does not have valid webpMetadata.")
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return .invalid
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}
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isAnimated = webpMetadata.frameCount > 1
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case .png:
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guard let isAnimatedPng = isAnimatedPngData() else {
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Logger.warn("Could not determine if png is animated.")
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return .invalid
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}
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isAnimated = isAnimatedPng.boolValue
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default:
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isAnimated = false
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}
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if !ignorePerTypeFileSizeLimits {
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if isAnimated, byteLength > OWSMediaUtils.kMaxFileSizeAnimatedImage {
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Logger.warn("Oversize image.")
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return .imageTypeSizeLimitExceeded
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} else if !isAnimated, byteLength > OWSMediaUtils.kMaxFileSizeImage {
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Logger.warn("Oversize image.")
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return .imageTypeSizeLimitExceeded
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}
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}
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let metadata = imageMetadata(withIsAnimated: isAnimated, imageFormat: imageFormat)
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guard let metadata else {
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return .invalid
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}
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return .valid(metadata)
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}
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fileprivate func imageMetadata(withIsAnimated isAnimated: Bool, imageFormat: ImageFormat) -> ImageMetadata? {
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if imageFormat == .webp {
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let imageSize = sizeForWebpData
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guard Data.ows_isValidImage(dimension: imageSize, depthBytes: 1, isAnimated: isAnimated) else {
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Logger.warn("Image does not have valid dimensions: \(imageSize)")
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return nil
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}
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return .init(imageFormat: imageFormat, pixelSize: imageSize, hasAlpha: true, isAnimated: isAnimated)
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}
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guard let imageSource = try? self.cgImageSource() else {
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Logger.warn("Could not build imageSource.")
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return nil
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}
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return Data.imageMetadata(withImageSource: imageSource, imageFormat: imageFormat, isAnimated: isAnimated)
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}
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fileprivate static func imageMetadata(withImageSource imageSource: CGImageSource, imageFormat: ImageFormat, isAnimated: Bool) -> ImageMetadata? {
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let options = [kCGImageSourceShouldCache as String: false]
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guard let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, options as CFDictionary) as? [String: AnyObject] else {
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Logger.warn("Missing imageProperties.")
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return nil
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}
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guard let widthNumber = imageProperties[kCGImagePropertyPixelWidth as String] as? NSNumber else {
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Logger.warn("widthNumber was unexpectedly nil")
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return nil
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}
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guard let heightNumber = imageProperties[kCGImagePropertyPixelHeight as String] as? NSNumber else {
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Logger.warn("heightNumber was unexpectedly nil")
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return nil
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}
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var pixelSize = CGSize(width: widthNumber.doubleValue, height: heightNumber.doubleValue)
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if let orientationNumber = imageProperties[kCGImagePropertyOrientation as String] as? NSNumber {
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guard let orientation = CGImagePropertyOrientation(rawValue: orientationNumber.uint32Value) else {
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Logger.warn("orientation number was invalid")
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return nil
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}
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pixelSize = applyImageOrientation(orientation, to: pixelSize)
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}
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let hasAlpha = imageProperties[kCGImagePropertyHasAlpha as String] as? NSNumber ?? false
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// The number of bits in each color sample of each pixel. The value of this key is a CFNumberRef.
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guard let depthNumber = imageProperties[kCGImagePropertyDepth as String] as? NSNumber else {
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Logger.warn("depthNumber was unexpectedly nil")
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return nil
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}
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let depthBits = depthNumber.uintValue
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// This should usually be 1.
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let depthBytes = ceil(Double(depthBits) / 8.0)
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// The color model of the image such as "RGB", "CMYK", "Gray", or "Lab". The value of this key is CFStringRef.
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guard let colorModel = (imageProperties[kCGImagePropertyColorModel as String] as? NSString) as String? else {
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Logger.warn("colorModel was unexpectedly nil")
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return nil
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}
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guard colorModel == kCGImagePropertyColorModelRGB as String || colorModel == kCGImagePropertyColorModelGray as String else {
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Logger.warn("Invalid colorModel: \(colorModel)")
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return nil
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}
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guard ows_isValidImage(dimension: pixelSize, depthBytes: depthBytes, isAnimated: isAnimated) else {
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Logger.warn("Image does not have valid dimensions: \(pixelSize).")
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return nil
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}
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return .init(imageFormat: imageFormat, pixelSize: pixelSize, hasAlpha: hasAlpha.boolValue, isAnimated: isAnimated)
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}
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// MARK: - WEBP
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public func stillForWebpData() -> UIImage? {
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guard ows_guessImageFormat() == .webp else {
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owsFailDebug("Invalid webp image.")
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return nil
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}
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guard let data = try? self.readIntoMemory() else {
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return nil
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}
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return UIImage.sd_image(with: data)
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}
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fileprivate static func isWebp(filePath: String) -> Bool {
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let fileExtension = ((filePath as NSString).lastPathComponent as NSString).pathExtension.lowercased()
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return "webp" == fileExtension
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}
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fileprivate var sizeForWebpData: CGSize {
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let webpMetadata = metadataForWebp
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guard webpMetadata.isValid else {
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return .zero
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}
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return .init(width: CGFloat(webpMetadata.canvasWidth), height: CGFloat(webpMetadata.canvasHeight))
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}
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fileprivate var metadataForWebp: WebpMetadata {
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guard let data = try? self.readIntoMemory() else {
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return WebpMetadata(isValid: false, canvasWidth: 0, canvasHeight: 0, frameCount: 0)
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}
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guard let image = SDAnimatedImage(data: data) else {
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return WebpMetadata(isValid: false, canvasWidth: 0, canvasHeight: 0, frameCount: 0)
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}
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let count = image.sd_imageFrameCount
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let height = image.pixelHeight
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let width = image.pixelWidth
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return WebpMetadata(
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isValid: width > 0 && height > 0 && count > 0,
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canvasWidth: UInt32(width),
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canvasHeight: UInt32(height),
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frameCount: UInt32(count)
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)
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}
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}
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