From 1d32dc9067ca172a8e1aa77fc7e5a30cb978a48a Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Thu, 11 Mar 2021 17:45:44 +0000
Subject: [PATCH] Support downloading bottles from GitHub Packages

---
 Library/Homebrew/download_strategy.rb | 23 +++++++++++++++++++++++
 Library/Homebrew/software_spec.rb     |  4 ++++
 2 files changed, 27 insertions(+)

diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 206962ac74..bf52bc08a2 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -13,6 +13,8 @@ require "mechanize/http/content_disposition_parser"
 
 require "utils/curl"
 
+require "github_packages"
+
 # @abstract Abstract superclass for all download strategies.
 #
 # @api private
@@ -527,6 +529,25 @@ class CurlDownloadStrategy < AbstractFileDownloadStrategy
   end
 end
 
+# Strategy for downloading a file from an GitHub Packages URL.
+#
+# @api public
+class CurlGitHubPackagesDownloadStrategy < CurlDownloadStrategy
+  attr_accessor :checksum, :name
+
+  private
+
+  def _fetch(url:, resolved_url:)
+    raise "Empty checksum" if checksum.blank?
+    raise "Empty name" if name.blank?
+
+    _, org, repo, = *url.match(GitHubPackages::URL_REGEX)
+
+    blob_url = "https://ghcr.io/v2/#{org}/#{repo}/#{name}/blobs/sha256:#{checksum}"
+    curl_download(blob_url, "--header", "Authorization: Bearer", to: temporary_path)
+  end
+end
+
 # Strategy for downloading a file from an Apache Mirror URL.
 #
 # @api public
@@ -1243,6 +1264,8 @@ class DownloadStrategyDetector
 
   def self.detect_from_url(url)
     case url
+    when GitHubPackages::URL_REGEX
+      CurlGitHubPackagesDownloadStrategy
     when %r{^https?://github\.com/[^/]+/[^/]+\.git$}
       GitHubGitDownloadStrategy
     when %r{^https?://.+\.git$},
diff --git a/Library/Homebrew/software_spec.rb b/Library/Homebrew/software_spec.rb
index e53bf90728..62fcd9fefd 100644
--- a/Library/Homebrew/software_spec.rb
+++ b/Library/Homebrew/software_spec.rb
@@ -316,12 +316,16 @@ class Bottle
 
   def fetch(verify_download_integrity: true)
     # add the default bottle domain as a fallback mirror
+    # TODO: this may need adjusted when if we use GitHub Packages by default
     if @resource.download_strategy == CurlDownloadStrategy &&
        @resource.url.start_with?(Homebrew::EnvConfig.bottle_domain)
       fallback_url = @resource.url
                               .sub(/^#{Regexp.escape(Homebrew::EnvConfig.bottle_domain)}/,
                                    HOMEBREW_BOTTLE_DEFAULT_DOMAIN)
       @resource.mirror(fallback_url) if [@resource.url, *@resource.mirrors].exclude?(fallback_url)
+    elsif @resource.download_strategy == CurlGitHubPackagesDownloadStrategy
+      @resource.downloader.name = @name
+      @resource.downloader.checksum = @resource.checksum.hexdigest
     end
     @resource.fetch(verify_download_integrity: verify_download_integrity)
   end