source/blender/blendthumb/CMakeLists.txt

@@ -57,12 +57,12 @@ if(UNIX AND NOT APPLE)
 endif()
 
 if(APPLE)
-  set(SRC
+  set(SRC_APPEX
     src/ThumbnailProvider.mm
     src/ThumbnailProvider.h
   )
 
-  add_executable(blender-thumbnailer MACOSX_BUNDLE ${SRC})
+  add_executable(blender-thumbnailer MACOSX_BUNDLE ${SRC} ${SRC_APPEX})
   setup_platform_linker_flags(blender-thumbnailer)
   target_link_libraries(blender-thumbnailer
     bf_blenlib

source/blender/blendthumb/src/ThumbnailProvider.mm

@@ -1,6 +1,15 @@
 
 #include "ThumbnailProvider.h"
 
+#include <AppKit/NSImage.h>
+#include <CoreGraphics/CGDataProvider.h>
+#include <CoreGraphics/CoreGraphics.h>
+#include <Foundation/Foundation.h>
+
+#include "BLI_fileops.h"
+#include "BLI_filereader.h"
+#include "blendthumb.hh"
+
 /**
  * This section intends to list the important steps for creating a thumbnail extension.
  * qlgenerator has been deprecated and removed in platforms we support. App extensions are the way
@@ -38,17 +47,88 @@
  *
  * # Troubleshooting
  * - Is it registered with lsregister and there isn't a conflict with another plugin taking
- * precendence?
- * - Is it codesigned and sandboxed?
+ * precendence? `lsregister -dump | grep Blender.app/`
+ * - Is it codesigned and sandboxed? `codesign -d --entitlements - /path/to/plugin`
  * - Sometimes blender-thumbnailer running in background can be killed.
  * - qlmanage -r && killall Finder
- * - lsregister -dump | grep Blender.app/
  *
  * # Triggering a thumbnail
  * - qlmanage -t /path/to/file.blend
  * - qlmanage -t -s 512 -o /tmp/ /path/to/file.blend
  */
 
+class FileReaderRAII {
+  int src_file_ = -1;
+
+ public:
+  explicit FileReaderRAII(int src_file) : src_file_(src_file) {}
+  ~FileReaderRAII()
+  {
+    if (src_file_ != -1) {
+      close(src_file_);
+    }
+  }
+
+  bool good()
+  {
+    return src_file_ != -1;
+  }
+
+  int get()
+  {
+    return src_file_;
+  }
+};
+
+static NSError *createErrorFromStr(NSString *errorStr)
+{
+  NSLog(@"Blender Thumbnailer Error: %@", errorStr);
+  return [NSError errorWithDomain:@"com.blenderfoundation.blender.thumbnailer"
+                             code:-1
+                         userInfo:@{NSLocalizedDescriptionKey : errorStr}];
+}
+
+static NSImage *generateNSImageForFile(const char *src_blend_path, NSError **error)
+{
+
+  /* Open source file `src_blend`. */
+  FileReaderRAII src_file_fd = FileReaderRAII(BLI_open(src_blend_path, O_BINARY | O_RDONLY, 0));
+  if (!src_file_fd.good()) {
+    *error = createErrorFromStr(@"Failed to open blend");
+    return nil;
+  }
+
+  FileReader *file_content = BLI_filereader_new_file(src_file_fd.get());
+  if (file_content == nullptr) {
+    *error = createErrorFromStr(@"Failed to read from blend");
+    return nil;
+  }
+
+  /* Extract thumbnail from file. */
+  Thumbnail thumb;
+  eThumbStatus err = blendthumb_create_thumb_from_file(file_content, &thumb);
+  if (err != BT_OK) {
+    *error = createErrorFromStr(@"Failed to create thumbnail from file");
+    return nil;
+  }
+
+  std::optional<blender::Vector<uint8_t>> png_buf_opt = blendthumb_create_png_data_from_thumb(
+      &thumb);
+  if (!png_buf_opt) {
+    *error = createErrorFromStr(@"Failed to create png data from thumbnail");
+    return nil;
+  }
+  NSData *data = [NSData dataWithBytes:png_buf_opt->data() length:png_buf_opt->size()];
+  CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)data);
+  CGImageRef image = CGImageCreateWithPNGDataProvider(
+      provider, nullptr, true, kCGRenderingIntentDefault);
+  CGDataProviderRelease(provider);
+  NSImage *uiimage = [[NSImage alloc] initWithCGImage:image size:NSZeroSize];
+  CGImageRelease(image);
+  CGDataProviderRelease(provider);
+  return uiimage;
+}
+
 @implementation ThumbnailProvider
 
 - (void)provideThumbnailForFileRequest:(QLFileThumbnailRequest *)request
@@ -56,13 +136,24 @@
                                                  NSError *_Nullable error))handler
 {
 
-  NSLog(@"hello world from blender");
-  NSURL *foo = [[NSURL alloc] initFileURLWithFileSystemRepresentation:""
-                                                          isDirectory:NO
-                                                        relativeToURL:nil];
-  QLThumbnailReply *reply = [QLThumbnailReply replyWithImageFileURL:foo];
-
-  handler(reply, nil);
+  NSLog(@"Generating thumbnail for %@", request.fileURL.path);
+  @autoreleasepool {
+    NSError *error = nil;
+    NSImage *image = generateNSImageForFile(request.fileURL.path.UTF8String, &error);
+    if (image == nil) {
+      handler(nil, error);
+      return;
+    }
+    handler([QLThumbnailReply replyWithContextSize:request.maximumSize
+                        currentContextDrawingBlock:^BOOL {
+                          [image drawInRect:NSMakeRect(0,
+                                                       0,
+                                                       request.maximumSize.width,
+                                                       request.maximumSize.height)];
+                          return YES;
+                        }],
+            nil);
+  }
 }
 
 @end