Refactor image loading code to separate method

Now we use RCTConvert in debug mode & RCTImageLoader in release.

Author: kkafar

ios/RNSBarButtonItem.mm

@@ -2,7 +2,7 @@
 #import <React/RCTConvert.h>
 #import <React/RCTFont.h>
 #import <React/RCTImageSource.h>
-#import <objc/runtime.h>
+#import "RCTImageSource+AccessHiddenMembers.h"
 #import "RNSDefines.h"
 
 @implementation RNSBarButtonItem {
@@ -22,39 +22,25 @@ - (instancetype)initWithConfig:(NSDictionary<NSString *, id> *)dict
 
   NSString *title = dict[@"title"];
   NSDictionary *imageSourceObj = dict[@"imageSource"];
-  if (imageSourceObj) {
-    if (imageSourceObj[@"__packager_asset"]) {
-      self.title = title;
-      self.image = [RCTConvert UIImage:imageSourceObj];
-    } else {
-      RCTImageSource *imageSource = [RCTConvert RCTImageSource:imageSourceObj];
-      [imageLoader loadImageWithURLRequest:imageSource.request
-          size:imageSource.size
-          scale:imageSource.scale
-          clipped:true
-          resizeMode:RCTResizeModeContain
-          progressBlock:^(int64_t progress, int64_t total) {
-          }
-          partialLoadBlock:^(UIImage *_Nonnull image) {
-          }
-          completionBlock:^(NSError *_Nullable error, UIImage *_Nullable image) {
-            dispatch_async(dispatch_get_main_queue(), ^{
-              self.image = image;
-              self.title = title;
-            });
-          }];
-    }
-  } else if (title) {
-    self.title = title;
-  }
   NSString *sfSymbolName = dict[@"sfSymbolName"];
-  if (sfSymbolName) {
+
+  if (imageSourceObj != nil) {
+    void (^completionAction)(NSError *_Nullable, UIImage *_Nullable) =
+        ^(NSError *_Nullable error, UIImage *_Nullable image) {
+          self.image = image;
+        };
+    [self loadImageSyncFromImageSourceJson:imageSourceObj withImageLoader:imageLoader completionBlock:completionAction];
+  } else if (sfSymbolName != nil) {
     self.image = [UIImage systemImageNamed:sfSymbolName];
   }
 
-  NSDictionary *titleStyle = dict[@"titleStyle"];
-  if (titleStyle) {
-    [self setTitleStyleFromConfig:titleStyle];
+  if (title != nil) {
+    self.title = title;
+
+    NSDictionary *titleStyle = dict[@"titleStyle"];
+    if (titleStyle != nil) {
+      [self setTitleStyleFromConfig:titleStyle];
+    }
   }
 
   id tintColorObj = dict[@"tintColor"];
@@ -332,4 +318,55 @@ - (void)setBadgeFromConfig:(NSDictionary *)badgeObj
 }
 #endif
 
+/**
+ * Should be called from UI thread only. If done so, the method **tries** to load the image synchronously.
+ * There is no guarantee, because in release mode we rely on `RCTImageLoader` implementation details.
+ * No matter how the image is loaded, `completionBlock` is executed on main queue.
+ */
+- (void)loadImageSyncFromImageSourceJson:(nonnull NSDictionary *)imageSourceJson
+                         withImageLoader:(nullable RCTImageLoader *)imageLoader
+                         completionBlock:
+                             (void (^_Nonnull)(NSError *_Nullable error, UIImage *_Nullable image))completion
+{
+  RCTAssert(RCTIsMainQueue(), @"[RNScreens] Expected to run on main queue");
+
+  RCTImageSource *imageSource = [RCTConvert RCTImageSource:imageSourceJson];
+  RCTAssert(imageSource != nil, @"[RNScreens] Expected nonnill image source");
+
+  // We use `+ [RCTConvert UIImage:]` only in debug mode, because it is deprecated, however
+  // I haven't found different way to load image synchronously in debug other than
+  // writing the code manually.
+
+#if !defined(NDEBUG) // We're in debug mode here
+  if (!imageSource.packagerAsset) {
+    // This is rather unexpected. In debug mode local asset should be sourced from packager.
+    RCTLogWarn(@"[RNScreens] Unexpected case during image load: loading not a packager asset");
+  }
+
+  // Try to load anyway.
+  UIImage *loadedImage = [RCTConvert UIImage:imageSourceJson];
+  completion(nil, loadedImage);
+  return;
+#else // We're in release mode here
+  [imageLoader loadImageWithURLRequest:imageSource.request
+      size:imageSource.size
+      scale:imageSource.scale
+      clipped:true
+      resizeMode:RCTResizeModeContain
+      progressBlock:^(int64_t progress, int64_t total) {
+      }
+      partialLoadBlock:^(UIImage *_Nonnull image) {
+      }
+      completionBlock:^(NSError *_Nullable error, UIImage *_Nullable image) {
+        if (RCTIsMainQueue()) {
+          completion(error, image);
+        } else {
+          dispatch_async(dispatch_get_main_queue(), ^{
+            completion(error, image);
+          });
+        }
+      }];
+#endif
+}
+
 @end

ios/utils/extensions/RCTImageSource+AccessHiddenMembers.h

@@ -0,0 +1,9 @@
+#pragma once
+
+// This field should exist in extension in `RCTImageSource.m`
+
+@interface RCTImageSource (AccessHiddenMembers)
+
+@property (nonatomic, assign) BOOL packagerAsset;
+
+@end