1 files changed, 121 insertions, 56 deletions
diff --git a/app/models/blob.rb b/app/models/blob.rb
index 55872acef51..1cdb8811cff 100644
--- a/app/models/blob.rb
+++ b/app/models/blob.rb
@@ -3,8 +3,42 @@ class Blob < SimpleDelegator
   CACHE_TIME = 60 # Cache raw blobs referred to by a (mutable) ref for 1 minute
   CACHE_TIME_IMMUTABLE = 3600 # Cache blobs referred to by an immutable reference for 1 hour
 
-  # The maximum size of an SVG that can be displayed.
-  MAXIMUM_SVG_SIZE = 2.megabytes
+  MAXIMUM_TEXT_HIGHLIGHT_SIZE = 1.megabyte
+
+  # Finding a viewer for a blob happens based only on extension and whether the
+  # blob is binary or text, which means 1 blob should only be matched by 1 viewer,
+  # and the order of these viewers doesn't really matter.
+  #
+  # However, when the blob is an LFS pointer, we cannot know for sure whether the
+  # file being pointed to is binary or text. In this case, we match only on
+  # extension, preferring binary viewers over text ones if both exist, since the
+  # large files referred to in "Large File Storage" are much more likely to be
+  # binary than text.
+  #
+  # `.stl` files, for example, exist in both binary and text forms, and are
+  # handled by different viewers (`BinarySTL` and `TextSTL`) depending on blob
+  # type. LFS pointers to `.stl` files are assumed to always be the binary kind,
+  # and use the `BinarySTL` viewer.
+  RICH_VIEWERS = [
+    BlobViewer::Markup,
+    BlobViewer::Notebook,
+    BlobViewer::SVG,
+
+    BlobViewer::Image,
+    BlobViewer::Sketch,
+
+    BlobViewer::Video,
+    
+    BlobViewer::PDF,
+
+    BlobViewer::BinarySTL,
+    BlobViewer::TextSTL,
+  ].freeze
+
+  BINARY_VIEWERS = RICH_VIEWERS.select(&:binary?).freeze
+  TEXT_VIEWERS = RICH_VIEWERS.select(&:text?).freeze
+
+  attr_reader :project
 
   # Wrap a Gitlab::Git::Blob object, or return nil when given nil
   #
@@ -16,10 +50,16 @@ class Blob < SimpleDelegator
   #
   #     blob = Blob.decorate(nil)
   #     puts "truthy" if blob # No output
-  def self.decorate(blob)
+  def self.decorate(blob, project = nil)
     return if blob.nil?
 
-    new(blob)
+    new(blob, project)
+  end
+
+  def initialize(blob, project = nil)
+    @project = project
+
+    super(blob)
   end
 
   # Returns the data of the blob.
@@ -35,82 +75,107 @@ class Blob < SimpleDelegator
   end
 
   def no_highlighting?
-    size && size > 1.megabyte
+    size && size > MAXIMUM_TEXT_HIGHLIGHT_SIZE
   end
 
-  def only_display_raw?
+  def too_large?
     size && truncated?
   end
 
+  # Returns the size of the file that this blob represents. If this blob is an
+  # LFS pointer, this is the size of the file stored in LFS. Otherwise, this is
+  # the size of the blob itself.
+  def raw_size
+    if valid_lfs_pointer?
+      lfs_size
+    else
+      size
+    end
+  end
+
+  # Returns whether the file that this blob represents is binary. If this blob is
+  # an LFS pointer, we assume the file stored in LFS is binary, unless a
+  # text-based rich blob viewer matched on the file's extension. Otherwise, this
+  # depends on the type of the blob itself.
+  def raw_binary?
+    if valid_lfs_pointer?
+      if rich_viewer
+        rich_viewer.binary?
+      else
+        true
+      end
+    else
+      binary?
+    end
+  end
+
   def extension
-    extname.downcase.delete('.')
+    @extension ||= extname.downcase.delete('.')
   end
 
-  def svg?
-    text? && language && language.name == 'SVG'
+  def video?
+    UploaderHelper::VIDEO_EXT.include?(extension)
   end
 
-  def pdf?
-    extension == 'pdf'
+  def readable_text?
+    text? && !valid_lfs_pointer? && !too_large?
   end
 
-  def ipython_notebook?
-    text? && language&.name == 'Jupyter Notebook'
+  def valid_lfs_pointer?
+    lfs_pointer? && project&.lfs_enabled?
   end
 
-  def sketch?
-    binary? && extension == 'sketch'
+  def invalid_lfs_pointer?
+    lfs_pointer? && !project&.lfs_enabled?
   end
 
-  def stl?
-    extension == 'stl'
+  def simple_viewer
+    @simple_viewer ||= simple_viewer_class.new(self)
   end
 
-  def markup?
-    text? && Gitlab::MarkupHelper.markup?(name)
+  def rich_viewer
+    return @rich_viewer if defined?(@rich_viewer)
+
+    @rich_viewer = rich_viewer_class&.new(self)
   end
 
-  def size_within_svg_limits?
-    size <= MAXIMUM_SVG_SIZE
+  def rendered_as_text?(ignore_errors: true)
+    simple_viewer.text? && (ignore_errors || simple_viewer.render_error.nil?)
   end
 
-  def video?
-    UploaderHelper::VIDEO_EXT.include?(extname.downcase.delete('.'))
+  def show_viewer_switcher?
+    rendered_as_text? && rich_viewer
   end
 
-  def to_partial_path(project)
-    if lfs_pointer?
-      if project.lfs_enabled?
-        'download'
-      else
-        'text'
-      end
-    elsif image?
-      'image'
-    elsif svg?
-      'svg'
-    elsif pdf?
-      'pdf'
-    elsif ipython_notebook?
-      'notebook'
-    elsif sketch?
-      'sketch'
-    elsif stl?
-      'stl'
-    elsif markup?
-      if only_display_raw?
-        'too_large'
-      else
-        'markup'
-      end
-    elsif text?
-      if only_display_raw?
-        'too_large'
-      else
-        'text'
-      end
-    else
-      'download'
+  def override_max_size!
+    simple_viewer&.override_max_size = true
+    rich_viewer&.override_max_size = true
+  end
+
+  private
+
+  def simple_viewer_class
+    if empty?
+      BlobViewer::Empty
+    elsif raw_binary?
+      BlobViewer::Download
+    else # text
+      BlobViewer::Text
     end
   end
+
+  def rich_viewer_class
+    return if invalid_lfs_pointer? || empty?
+
+    classes =
+      if valid_lfs_pointer?
+        BINARY_VIEWERS + TEXT_VIEWERS
+      elsif binary?
+        BINARY_VIEWERS
+      else # text
+        TEXT_VIEWERS
+      end
+
+    classes.find { |viewer_class| viewer_class.can_render?(self) }
+  end
 end