1 files changed, 135 insertions, 0 deletions
diff --git a/lib/rubygems/source/local.rb b/lib/rubygems/source/local.rb
new file mode 100644
index 0000000000..4bef31a265
--- /dev/null
+++ b/lib/rubygems/source/local.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+##
+# The local source finds gems in the current directory for fulfilling
+# dependencies.
+
+class Gem::Source::Local < Gem::Source
+  def initialize # :nodoc:
+    @specs   = nil
+    @api_uri = nil
+    @uri     = nil
+    @load_specs_names = {}
+  end
+
+  ##
+  # Local sorts before Gem::Source and after Gem::Source::Installed
+
+  def <=>(other)
+    case other
+    when Gem::Source::Installed,
+         Gem::Source::Lock then
+      -1
+    when Gem::Source::Local then
+      0
+    when Gem::Source then
+      1
+    end
+  end
+
+  def inspect # :nodoc:
+    keys = @specs ? @specs.keys.sort : "NOT LOADED"
+    format("#<%s specs: %p>", self.class, keys)
+  end
+
+  def load_specs(type) # :nodoc:
+    @load_specs_names[type] ||= begin
+      names = []
+
+      @specs = {}
+
+      Dir["*.gem"].each do |file|
+        pkg = Gem::Package.new(file)
+        spec = pkg.spec
+      rescue SystemCallError, Gem::Package::FormatError
+        # ignore
+      else
+        tup = spec.name_tuple
+        @specs[tup] = [File.expand_path(file), pkg]
+
+        case type
+        when :released
+          unless pkg.spec.version.prerelease?
+            names << pkg.spec.name_tuple
+          end
+        when :prerelease
+          if pkg.spec.version.prerelease?
+            names << pkg.spec.name_tuple
+          end
+        when :latest
+          tup = pkg.spec.name_tuple
+
+          cur = names.find {|x| x.name == tup.name }
+          if !cur
+            names << tup
+          elsif cur.version < tup.version
+            names.delete cur
+            names << tup
+          end
+        else
+          names << pkg.spec.name_tuple
+        end
+      end
+
+      names
+    end
+  end
+
+  def find_gem(gem_name, version = Gem::Requirement.default, prerelease = false) # :nodoc:
+    find_all_gems(gem_name, version, prerelease).max_by(&:version)
+  end
+
+  def find_all_gems(gem_name, version = Gem::Requirement.default, prerelease = false) # :nodoc:
+    load_specs :complete
+
+    found = []
+
+    @specs.each do |n, data|
+      next unless n.name == gem_name
+      s = data[1].spec
+
+      if version.satisfied_by?(s.version)
+        if prerelease
+          found << s
+        elsif !s.version.prerelease? || version.prerelease?
+          found << s
+        end
+      end
+    end
+
+    found
+  end
+
+  def fetch_spec(name) # :nodoc:
+    load_specs :complete
+
+    if data = @specs[name]
+      data.last.spec
+    else
+      raise Gem::Exception, "Unable to find spec for #{name.inspect}"
+    end
+  end
+
+  def download(spec, cache_dir = nil) # :nodoc:
+    load_specs :complete
+
+    @specs.each do |_name, data|
+      return data[0] if data[1].spec == spec
+    end
+
+    raise Gem::Exception, "Unable to find file for '#{spec.full_name}'"
+  end
+
+  def pretty_print(q) # :nodoc:
+    q.object_group(self) do
+      q.group 2, "[Local gems:", "]" do
+        q.breakable
+        if @specs
+          q.seplist @specs.keys do |v|
+            q.text v.full_name
+          end
+        end
+      end
+    end
+  end
+end