Handle UIImage shares.

SignalServiceKit/src/Util/OWSFileSystem.h

@@ -29,6 +29,9 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (NSArray<NSString *> *_Nullable)allFilesInDirectoryRecursive:(NSString *)dirPath error:(NSError **)error;
 
++ (NSString *)temporaryFilePath;
++ (NSString *)temporaryFilePathWithFileExtension:(NSString *_Nullable)fileExtension;
+
 // Returns nil on failure.
 + (nullable NSString *)writeDataToTemporaryFile:(NSData *)data fileExtension:(NSString *_Nullable)fileExtension;
 

SignalServiceKit/src/Util/OWSFileSystem.m

@@ -166,16 +166,28 @@ NS_ASSUME_NONNULL_BEGIN
     return filePaths;
 }
 
-+ (nullable NSString *)writeDataToTemporaryFile:(NSData *)data fileExtension:(NSString *_Nullable)fileExtension
++ (NSString *)temporaryFilePath
 {
-    OWSAssert(data);
+    return [self temporaryFilePathWithFileExtension:nil];
+}
 
++ (NSString *)temporaryFilePathWithFileExtension:(NSString *_Nullable)fileExtension
+{
     NSString *temporaryDirectory = NSTemporaryDirectory();
     NSString *tempFileName = NSUUID.UUID.UUIDString;
     if (fileExtension.length > 0) {
         tempFileName = [[tempFileName stringByAppendingString:@"."] stringByAppendingString:fileExtension];
     }
     NSString *tempFilePath = [temporaryDirectory stringByAppendingPathComponent:tempFileName];
+
+    return tempFilePath;
+}
+
++ (nullable NSString *)writeDataToTemporaryFile:(NSData *)data fileExtension:(NSString *_Nullable)fileExtension
+{
+    OWSAssert(data);
+
+    NSString *tempFilePath = [self temporaryFilePathWithFileExtension:fileExtension];
     NSError *error;
     BOOL success = [data writeToFile:tempFilePath options:NSDataWritingAtomic error:&error];
     if (!success || error) {

SignalShareExtension/ShareViewController.swift

@@ -608,6 +608,19 @@ public class ShareViewController: UINavigationController, ShareViewDelegate, SAE
                 } else {
                     fulfill((itemUrl: url, utiType: srcUtiType))
                 }
+            } else if let image = value as? UIImage {
+                if let data = UIImagePNGRepresentation(image) {
+                    let tempFilePath = OWSFileSystem.temporaryFilePath(withFileExtension:"png")
+                    do {
+                        let url = NSURL.fileURL(withPath:tempFilePath)
+                        try data.write(to: url, options: .atomicWrite)
+                        fulfill((url, srcUtiType))
+                    } catch {
+                        reject(ShareViewControllerError.assertionError(description: "couldn't write UIImage: \(String(describing: error))"))
+                    }
+                } else {
+                    reject(ShareViewControllerError.assertionError(description: "couldn't convert UIImage to PNG: \(String(describing: error))"))
+                }
             } else {
                 // It's unavoidable that we may sometimes receives data types that we
                 // don't know how to handle.