1 files changed, 84 insertions, 0 deletions
diff --git a/lib/bundler/compact_index_client/parser.rb b/lib/bundler/compact_index_client/parser.rb
new file mode 100644
index 0000000000..3276abdd68
--- /dev/null
+++ b/lib/bundler/compact_index_client/parser.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+module Bundler
+  class CompactIndexClient
+    class Parser
+      # `compact_index` - an object responding to #names, #versions, #info(name, checksum),
+      #                   returning the file contents as a string
+      def initialize(compact_index)
+        @compact_index = compact_index
+        @info_checksums = nil
+        @versions_by_name = nil
+        @available = nil
+        @gem_parser = nil
+      end
+
+      def names
+        lines(@compact_index.names)
+      end
+
+      def versions
+        @versions_by_name ||= Hash.new {|hash, key| hash[key] = [] }
+        @info_checksums = {}
+
+        lines(@compact_index.versions).each do |line|
+          name, versions_string, checksum = line.split(" ", 3)
+          @info_checksums[name] = checksum || ""
+          versions_string.split(",") do |version|
+            delete = version.delete_prefix!("-")
+            version = version.split("-", 2).unshift(name)
+            if delete
+              @versions_by_name[name].delete(version)
+            else
+              @versions_by_name[name] << version
+            end
+          end
+        end
+
+        @versions_by_name
+      end
+
+      def info(name)
+        data = @compact_index.info(name, info_checksums[name])
+        lines(data).map {|line| gem_parser.parse(line).unshift(name) }
+      end
+
+      def available?
+        return @available unless @available.nil?
+        @available = !info_checksums.empty?
+      end
+
+      private
+
+      def info_checksums
+        @info_checksums ||= lines(@compact_index.versions).each_with_object({}) do |line, checksums|
+          parse_version_checksum(line, checksums)
+        end
+      end
+
+      def lines(data)
+        return [] if data.nil? || data.empty?
+        lines = data.split("\n")
+        header = lines.index("---")
+        header ? lines[header + 1..-1] : lines
+      end
+
+      def gem_parser
+        @gem_parser ||= GemParser.new
+      end
+
+      # This is mostly the same as `split(" ", 3)` but it avoids allocating extra objects.
+      # This method gets called at least once for every gem when parsing versions.
+      def parse_version_checksum(line, checksums)
+        return unless (name_end = line.index(" ")) # Artifactory bug causes blank lines in artifactor index files
+        return unless (checksum_start = line.index(" ", name_end + 1) + 1)
+        checksum_end = line.size - checksum_start
+
+        line.freeze # allows slicing into the string to not allocate a copy of the line
+        name = line[0, name_end]
+        checksum = line[checksum_start, checksum_end]
+        checksums[name.freeze] = checksum # freeze name since it is used as a hash key
+      end
+    end
+  end
+end