Use cache_store for descriptions

This makes use of both the existing interfaces and could use the
existing cache file but we'll create a new one and cleanup the old one
to avoid issues and use a more consistent name.

Library/Homebrew/cache_store.rb

@@ -49,6 +49,28 @@ class CacheStoreDatabase
     cache_path.exist?
   end
 
+  # Returns the modification time of the cache file (if it already exists).
+  #
+  # @return [Time]
+  def mtime
+    return unless created?
+    cache_path.mtime
+  end
+
+  # Performs a `select` on the underlying database.
+  #
+  # @return [Array]
+  def select(&block)
+    db.select(&block)
+  end
+
+  # Returns `true` if the cache is empty.
+  #
+  # @return [Boolean]
+  def empty?
+    db.empty?
+  end
+
   private
 
   # Lazily loaded database in read/write mode. If this method is called, a
@@ -105,14 +127,14 @@ class CacheStore
   # stored
   #
   # @abstract
-  def fetch_type(*)
+  def fetch(*)
     raise NotImplementedError
   end
 
   # Deletes data from the cache based on a condition defined in a concrete class
   #
   # @abstract
-  def flush_cache!
+  def delete!(*)
     raise NotImplementedError
   end
 

Library/Homebrew/cleanup.rb

@@ -161,7 +161,7 @@ module Homebrew
         cleanup_portable_ruby
         return if dry_run?
 
-        cleanup_linkage_db
+        cleanup_old_cache_db
         rm_ds_store
       else
         args.each do |arg|
@@ -325,8 +325,12 @@ module Homebrew
       end
     end
 
-    def cleanup_linkage_db
-      FileUtils.rm_rf [cache/"linkage.db", cache/"linkage.db.db"]
+    def cleanup_old_cache_db
+      FileUtils.rm_rf [
+        cache/"desc_cache.json",
+        cache/"linkage.db",
+        cache/"linkage.db.db",
+      ]
     end
 
     def rm_ds_store(dirs = nil)

Library/Homebrew/cmd/desc.rb

@@ -10,6 +10,7 @@
 
 require "descriptions"
 require "search"
+require "description_cache_store"
 
 module Homebrew
   module_function
@@ -21,23 +22,27 @@ module Homebrew
     search_type << :either if ARGV.flag? "--search"
     search_type << :name   if ARGV.flag? "--name"
     search_type << :desc   if ARGV.flag? "--description"
+    if search_type.size > 1
+      odie "Pick one, and only one, of -s/--search, -n/--name, or -d/--description."
+    elsif search_type.present? && ARGV.named.empty?
+      odie "You must provide a search term."
+    end
 
-    if search_type.empty?
+    results = if search_type.empty?
       raise FormulaUnspecifiedError if ARGV.named.empty?
 
       desc = {}
       ARGV.formulae.each { |f| desc[f.full_name] = f.desc }
-      results = Descriptions.new(desc)
-      results.print
-    elsif search_type.size > 1
-      odie "Pick one, and only one, of -s/--search, -n/--name, or -d/--description."
-    elsif !ARGV.named.empty?
+      Descriptions.new(desc)
+    else
       arg = ARGV.named.join(" ")
       string_or_regex = query_regexp(arg)
-      results = Descriptions.search(string_or_regex, search_type.first)
-      results.print
-    else
-      odie "You must provide a search term."
+      CacheStoreDatabase.use(:descriptions) do |db|
+        cache_store = DescriptionCacheStore.new(db)
+        Descriptions.search(string_or_regex, search_type.first, cache_store)
+      end
     end
+
+    results.print
   end
 end

Library/Homebrew/cmd/update-report.rb

@@ -8,6 +8,7 @@ require "formulary"
 require "descriptions"
 require "cleanup"
 require "update_migrator"
+require "description_cache_store"
 
 module Homebrew
   module_function
@@ -127,7 +128,10 @@ module Homebrew
         hub.dump
         hub.reporters.each(&:migrate_tap_migration)
         hub.reporters.each(&:migrate_formula_rename)
-        Descriptions.update_cache(hub)
+        CacheStoreDatabase.use(:descriptions) do |db|
+          DescriptionCacheStore.new(db)
+                               .update_from_report!(hub)
+        end
       end
       puts if ARGV.include?("--preinstall")
     end

Library/Homebrew/description_cache_store.rb

@@ -0,0 +1,88 @@
+require "set"
+require "cache_store"
+require "searchable"
+
+#
+# `DescriptionCacheStore` provides methods to fetch and mutate linkage-specific data used
+# by the `brew linkage` command
+#
+class DescriptionCacheStore < CacheStore
+  include Searchable
+
+  # Inserts a formula description into the cache if it does not exist or
+  # updates the formula description if it does exist
+  #
+  # @param  [String] formula_name: the name of the formula to set
+  # @param  [String] description:  the description from the formula to set
+  # @return [nil]
+  def update!(formula_name, description)
+    database.set(formula_name, description)
+  end
+
+  # Delete the formula description from the `DescriptionCacheStore`
+  #
+  # @param  [String] formula_name: the name of the formula to delete
+  # @return [nil]
+  def delete!(formula_name)
+    database.delete(formula_name)
+  end
+
+  # If the database is empty `update!` it with all known formulae.
+  # @return [nil]
+  def populate_if_empty!
+    return unless database.empty?
+    Formula.each { |f| update!(f.full_name, f.desc) }
+  end
+
+  # Use an update report to update the `DescriptionCacheStore`.
+  #
+  # @param  [Report] report: an update report generated by cmd/update.rb
+  # @return [nil]
+  def update_from_report!(report)
+    return if report.empty?
+
+    renamings   = report.select_formula(:R)
+    alterations = report.select_formula(:A) +
+                  report.select_formula(:M) +
+                  renamings.map(&:last)
+
+    update_from_formula_names!(alterations)
+    delete_from_formula_names!(report.select_formula(:D) +
+                               renamings.map(&:first))
+  end
+
+  # Use an array of formulae names to update the `DescriptionCacheStore`.
+  #
+  # @param  [Array] formula_names: the formulae to update.
+  # @return [nil]
+  def update_from_formula_names!(formula_names)
+    formula_names.each do |name|
+      begin
+        update!(name, Formula[name].desc)
+      rescue FormulaUnavailableError, *FormulaVersions::IGNORED_EXCEPTIONS => e
+        p e
+        delete!(name)
+      end
+    end
+  end
+
+  # Use an array of formulae names to delete them from the `DescriptionCacheStore`.
+  #
+  # @param  [Array] formula_names: the formulae to delete.
+  # @return [nil]
+  def delete_from_formula_names!(formula_names)
+    formula_names.each(&method(:delete!))
+  end
+
+  private
+
+  # Not implemented; access is through `Searchable`.
+  def fetch
+    super
+  end
+
+  # `select` from the underlying database.
+  def select(&block)
+    database.select(&block)
+  end
+end

Library/Homebrew/descriptions.rb

@@ -6,113 +6,17 @@ require "searchable"
 class Descriptions
   extend Homebrew::Search
 
-  CACHE_FILE = HOMEBREW_CACHE + "desc_cache.json"
-
-  def self.cache
-    @cache || load_cache
-  end
-
-  # If the cache file exists, load it into, and return, a hash; otherwise,
-  # return nil.
-  def self.load_cache
-    @cache = JSON.parse(CACHE_FILE.read) if CACHE_FILE.exist?
-  end
-
-  # Write the cache to disk after ensuring the existence of the containing
-  # directory.
-  def self.save_cache
-    HOMEBREW_CACHE.mkpath
-    CACHE_FILE.atomic_write JSON.dump(@cache)
-  end
-
-  # Create a hash mapping all formulae to their descriptions;
-  # save it for future use.
-  def self.generate_cache
-    @cache = {}
-    Formula.each do |f|
-      @cache[f.full_name] = f.desc
-    end
-    save_cache
-  end
-
-  # Return true if the cache exists, and none of the Taps
-  # repos were updated more recently than it was.
-  def self.cache_fresh?
-    return false unless CACHE_FILE.exist?
-
-    cache_mtime = File.mtime(CACHE_FILE)
-
-    Tap.each do |tap|
-      next unless tap.git?
-
-      repo_mtime = File.mtime(tap.path/".git/refs/heads/master")
-      return false if repo_mtime > cache_mtime
-    end
-
-    true
-  end
-
-  # Create the cache if it doesn't already exist.
-  def self.ensure_cache
-    generate_cache unless cache_fresh? && cache
-  end
-
-  # Take a {Report}, as generated by cmd/update.rb.
-  # Unless the cache file exists, do nothing.
-  # If it does exist, but the Report is empty, just touch the cache file.
-  # Otherwise, use the report to update the cache.
-  def self.update_cache(report)
-    return unless CACHE_FILE.exist?
-
-    if report.empty?
-      FileUtils.touch CACHE_FILE
-    else
-      renamings = report.select_formula(:R)
-      alterations = report.select_formula(:A) + report.select_formula(:M) +
-                    renamings.map(&:last)
-      cache_formulae(alterations, save: false)
-      uncache_formulae(report.select_formula(:D) +
-                            renamings.map(&:first))
-    end
-  end
-
-  # Given an array of formula names, add them and their descriptions to the
-  # cache. Save the updated cache to disk, unless explicitly told not to.
-  def self.cache_formulae(formula_names, options = { save: true })
-    return unless cache
-
-    formula_names.each do |name|
-      begin
-        @cache[name] = Formulary.factory(name).desc
-      rescue FormulaUnavailableError, *FormulaVersions::IGNORED_EXCEPTIONS
-        @cache.delete(name)
-      end
-    end
-    save_cache if options[:save]
-  end
-
-  # Given an array of formula names, remove them and their descriptions from
-  # the cache. Save the updated cache to disk, unless explicitly told not to.
-  def self.uncache_formulae(formula_names, options = { save: true })
-    return unless cache
-
-    formula_names.each { |name| @cache.delete(name) }
-    save_cache if options[:save]
-  end
-
   # Given a regex, find all formulae whose specified fields contain a match.
-  def self.search(string_or_regex, field = :either)
-    ensure_cache
-
-    @cache.extend(Searchable)
+  def self.search(string_or_regex, field, cache_store)
+    cache_store.populate_if_empty!
 
     results = case field
     when :name
-      @cache.search(string_or_regex) { |name, _| name }
+      cache_store.search(string_or_regex) { |name, _| name }
     when :desc
-      @cache.search(string_or_regex) { |_, desc| desc }
+      cache_store.search(string_or_regex) { |_, desc| desc }
     when :either
-      @cache.search(string_or_regex)
+      cache_store.search(string_or_regex)
     end
 
     new(results)
@@ -129,7 +33,11 @@ class Descriptions
     blank = Formatter.warning("[no description]")
     @descriptions.keys.sort.each do |full_name|
       short_name = short_names[full_name]
-      printed_name = (short_name_counts[short_name] == 1) ? short_name : full_name
+      printed_name = if short_name_counts[short_name] == 1
+        short_name
+      else
+        full_name
+      end
       description = @descriptions[full_name] || blank
       puts "#{Tty.bold}#{printed_name}:#{Tty.reset} #{description}"
     end
@@ -143,6 +51,9 @@ class Descriptions
 
   def short_name_counts
     @short_name_counts ||=
-      short_names.values.each_with_object(Hash.new(0)) { |name, counts| counts[name] += 1 }
+      short_names.values
+                 .each_with_object(Hash.new(0)) do |name, counts|
+        counts[name] += 1
+      end
   end
 end

Library/Homebrew/keg.rb

@@ -303,7 +303,7 @@ class Keg
     CacheStoreDatabase.use(:linkage) do |db|
       break unless db.created?
 
-      LinkageCacheStore.new(path, db).flush_cache!
+      LinkageCacheStore.new(path, db).delete!
     end
 
     path.rmtree

Library/Homebrew/linkage_cache_store.rb

@@ -41,7 +41,7 @@ class LinkageCacheStore < CacheStore
   # @param  [Symbol] the type to fetch from the `LinkageCacheStore`
   # @raise  [TypeError] error if the type is not in `HASH_LINKAGE_TYPES`
   # @return [Hash]
-  def fetch_type(type)
+  def fetch(type)
     unless HASH_LINKAGE_TYPES.include?(type)
       raise TypeError, <<~EOS
         Can't fetch types that are not defined for the linkage store
@@ -53,8 +53,10 @@ class LinkageCacheStore < CacheStore
     fetch_hash_values(type)
   end
 
+  # Delete the keg from the `LinkageCacheStore`
+  #
   # @return [nil]
-  def flush_cache!
+  def delete!
     database.delete(@keg_path)
   end
 

Library/Homebrew/linkage_checker.rb

@@ -79,9 +79,9 @@ class LinkageChecker
     keg_files_dylibs = nil
 
     if rebuild_cache
-      store&.flush_cache!
+      store&.delete!
     else
-      keg_files_dylibs = store&.fetch_type(:keg_files_dylibs)
+      keg_files_dylibs = store&.fetch(:keg_files_dylibs)
     end
 
     keg_files_dylibs_was_empty = false

Library/Homebrew/search.rb

@@ -1,4 +1,5 @@
 require "searchable"
+require "description_cache_store"
 
 module Homebrew
   module Search
@@ -14,7 +15,10 @@ module Homebrew
 
     def search_descriptions(string_or_regex)
       ohai "Formulae"
-      Descriptions.search(string_or_regex, :desc).print
+      CacheStoreDatabase.use(:descriptions) do |db|
+        cache_store = DescriptionCacheStore.new(db)
+        Descriptions.search(string_or_regex, :desc, cache_store).print
+      end
     end
 
     def search_taps(query, silent: false)

Library/Homebrew/tap.rb

@@ -1,5 +1,6 @@
 require "extend/cachable"
 require "readall"
+require "description_cache_store"
 
 # a {Tap} is used to extend the formulae provided by Homebrew core.
 # Usually, it's synced with a remote git repository. And it's likely
@@ -299,7 +300,10 @@ class Tap
 
     formatted_contents = contents.presence&.to_sentence&.dup&.prepend(" ")
     puts "Tapped#{formatted_contents} (#{path.abv})." unless quiet
-    Descriptions.cache_formulae(formula_names)
+    CacheStoreDatabase.use(:descriptions) do |db|
+      DescriptionCacheStore.new(db)
+                           .update_from_formula_names!(formula_names)
+    end
 
     return if options[:clone_target]
     return unless private?
@@ -331,7 +335,10 @@ class Tap
     formatted_contents = contents.presence&.to_sentence&.dup&.prepend(" ")
 
     unpin if pinned?
-    Descriptions.uncache_formulae(formula_names)
+    CacheStoreDatabase.use(:descriptions) do |db|
+      DescriptionCacheStore.new(db)
+                           .delete_from_formula_names!(formula_names)
+    end
     Utils::Link.unlink_manpages(path)
     Utils::Link.unlink_completions(path)
     path.rmtree

Library/Homebrew/test/cmd/desc_spec.rb

@@ -1,6 +1,4 @@
 describe "brew desc", :integration_test do
-  let(:desc_cache) { HOMEBREW_CACHE/"desc_cache.json" }
-
   it "shows a given Formula's description" do
     setup_test_formula "testball"
 
@@ -9,14 +7,4 @@ describe "brew desc", :integration_test do
       .and not_to_output.to_stderr
       .and be_a_success
   end
-
-  describe "--description" do
-    it "creates a description cache" do
-      expect(desc_cache).not_to exist
-
-      expect { brew "desc", "--description", "testball" }.to be_a_success
-
-      expect(desc_cache).to exist
-    end
-  end
 end

Library/Homebrew/test/cmd/search_spec.rb

@@ -34,7 +34,7 @@ describe "brew search", :integration_test do
   end
 
   describe "--desc" do
-    let(:desc_cache) { HOMEBREW_CACHE/"desc_cache.json" }
+    let(:desc_cache) { HOMEBREW_CACHE/"descriptions.json" }
 
     it "supports searching in descriptions and creates a description cache" do
       expect(desc_cache).not_to exist

Library/Homebrew/test/description_cache_store_spec.rb

@@ -0,0 +1,50 @@
+require "description_cache_store"
+
+describe DescriptionCacheStore do
+  subject(:cache_store) { described_class.new(database) }
+
+  let(:database) { double("database") }
+  let(:formula_name) { "test_name" }
+  let(:description) { "test_description" }
+
+  describe "#update!" do
+    it "sets the formula description" do
+      expect(database).to receive(:set).with(formula_name, description)
+      cache_store.update!(formula_name, description)
+    end
+  end
+
+  describe "#delete!" do
+    it "deletes the formula description" do
+      expect(database).to receive(:delete).with(formula_name)
+      cache_store.delete!(formula_name)
+    end
+  end
+
+  describe "#update_from_report!" do
+    let(:report) { double(select_formula: [], empty?: false) }
+
+    it "reads from the report" do
+      cache_store.update_from_report!(report)
+    end
+  end
+
+  describe "#update_from_formula_names!" do
+    it "sets the formulae descriptions" do
+      f = formula do
+        url "url-1"
+        desc "desc"
+      end
+      expect(Formulary).to receive(:factory).with(f.name).and_return(f)
+      expect(database).to receive(:set).with(f.name, f.desc)
+      cache_store.update_from_formula_names!([f.name])
+    end
+  end
+
+  describe "#delete_from_formula_names!" do
+    it "deletes the formulae descriptions" do
+      expect(database).to receive(:delete).with(formula_name)
+      cache_store.delete_from_formula_names!([formula_name])
+    end
+  end
+end

Library/Homebrew/test/linkage_cache_store_spec.rb

@@ -43,27 +43,27 @@ describe LinkageCacheStore do
     end
   end
 
-  describe "#flush_cache!" do
+  describe "#delete!" do
     it "calls `delete` on the `database` with `keg_name` as parameter" do
       expect(database).to receive(:delete).with(keg_name)
-      subject.flush_cache!
+      subject.delete!
     end
   end
 
-  describe "#fetch_type" do
+  describe "#fetch" do
     context "`HASH_LINKAGE_TYPES.include?(type)`" do
       before do
         expect(database).to receive(:get).with(keg_name).and_return(nil)
       end
 
       it "returns a `Hash` of values" do
-        expect(subject.fetch_type(:keg_files_dylibs)).to be_an_instance_of(Hash)
+        expect(subject.fetch(:keg_files_dylibs)).to be_an_instance_of(Hash)
       end
     end
 
     context "`type` not in `HASH_LINKAGE_TYPES`" do
       it "raises a `TypeError` if the `type` is not supported" do
-        expect { subject.fetch_type(:bad_type) }.to raise_error(TypeError)
+        expect { subject.fetch(:bad_type) }.to raise_error(TypeError)
       end
     end
   end