Use vendored taglib for swig

This is working towards deterministic `rake swig` (see
#136).

tasks/ext.rake

@@ -1,22 +1,15 @@
 # frozen-string-literal: true
 
+require_relative 'taglib'
+
 # Extension tasks and cross-compiling
 
 host = 'i686-w64-mingw32'
-$plat = ENV['PLATFORM'] || 'i386-mingw32'
-
-taglib_version = ENV['TAGLIB_VERSION'] || '1.9.1'
-taglib = "taglib-#{taglib_version}"
-
-tmp = "#{Dir.pwd}/tmp"
-tmp_arch = "#{tmp}/#{$plat}"
 toolchain_file = "#{Dir.pwd}/ext/win.cmake"
-install_dir = "#{tmp_arch}/#{taglib}"
-install_dll = "#{install_dir}/bin/libtag.dll"
-install_so = "#{install_dir}/lib/libtag.so"
-$cross_config_options = ["--with-opt-dir=#{install_dir}"]
+install_dll = "#{Taglib.install_dir}/bin/libtag.dll"
+$cross_config_options = ["--with-opt-dir=#{Taglib.install_dir}"]
 
-taglib_url = "https://github.com/taglib/taglib/archive/v#{taglib_version}.tar.gz"
+taglib_url = "https://github.com/taglib/taglib/archive/v#{Taglib.version}.tar.gz"
 taglib_options = ['-DCMAKE_BUILD_TYPE=Release',
                   '-DBUILD_EXAMPLES=OFF',
                   '-DBUILD_TESTS=OFF',
@@ -27,7 +20,7 @@ taglib_options = ['-DCMAKE_BUILD_TYPE=Release',
 
 def configure_cross_compile(ext)
   ext.cross_compile = true
-  ext.cross_platform = $plat
+  ext.cross_platform = Taglib.plat
   ext.cross_config_options.concat($cross_config_options)
   ext.cross_compiling do |gem|
     gem.files << 'lib/libtag.dll'
@@ -75,37 +68,37 @@ task :cross do
   ENV['CXX'] = "#{host}-g++"
 end
 
-file "#{tmp_arch}/stage/lib/libtag.dll" => [install_dll] do |f|
+file "#{Taglib.tmp_arch}/stage/lib/libtag.dll" => [install_dll] do |f|
   install install_dll, f
 end
 
-file install_dll => ["#{tmp}/#{taglib}"] do
-  chdir "#{tmp}/#{taglib}" do
-    sh %(cmake -DCMAKE_INSTALL_PREFIX=#{install_dir} -DCMAKE_TOOLCHAIN_FILE=#{toolchain_file} #{taglib_options})
+file install_dll => ["#{Taglib.tmp}/#{Taglib.dir}"] do
+  chdir "#{Taglib.tmp}/#{taglib}" do
+    sh %(cmake -DCMAKE_INSTALL_PREFIX=#{Taglib.install_dir} -DCMAKE_TOOLCHAIN_FILE=#{toolchain_file} #{taglib_options})
     sh 'make VERBOSE=1'
     sh 'make install'
   end
 end
 
-task vendor: [install_so]
+task vendor: [Taglib.library]
 
-file install_so => ["#{tmp_arch}/#{taglib}", "#{tmp_arch}/#{taglib}-build", "#{tmp}/#{taglib}"] do
-  chdir "#{tmp_arch}/#{taglib}-build" do
-    sh %(cmake -DCMAKE_INSTALL_PREFIX=#{install_dir} #{taglib_options} #{tmp}/#{taglib})
-    sh 'make install VERBOSE=1'
+file Taglib.library => ["#{Taglib.tmp_arch}/#{Taglib.dir}", "#{Taglib.tmp_arch}/#{Taglib.dir}-build", "#{Taglib.tmp}/#{Taglib.dir}"] do
+  chdir "#{Taglib.tmp_arch}/#{Taglib.dir}-build" do
+    sh %(cmake -DCMAKE_INSTALL_PREFIX=#{Taglib.install_dir} #{taglib_options} #{Taglib.source})
+    sh 'make install -j 4 VERBOSE=1'
   end
 end
 
-directory "#{tmp_arch}/#{taglib}"
-directory "#{tmp_arch}/#{taglib}-build"
+directory "#{Taglib.tmp_arch}/#{Taglib.dir}"
+directory "#{Taglib.tmp_arch}/#{Taglib.dir}-build"
 
-file "#{tmp}/#{taglib}" => ["#{tmp}/#{taglib}.tar.gz"] do
-  chdir tmp do
-    sh "tar xzf #{taglib}.tar.gz"
+file Taglib.source => ["#{Taglib.tmp}/#{Taglib.dir}.tar.gz"] do
+  chdir Taglib.tmp do
+    sh "tar xzf #{Taglib.dir}.tar.gz"
   end
 end
 
-file "#{tmp}/#{taglib}.tar.gz" => [tmp] do |t|
+file "#{Taglib.tmp}/#{Taglib.dir}.tar.gz" => [Taglib.tmp] do |t|
   require 'open-uri'
   puts "Downloading #{taglib_url}"
 
@@ -114,4 +107,4 @@ file "#{tmp}/#{taglib}.tar.gz" => [tmp] do |t|
   end
 end
 
-directory tmp
+directory Taglib.tmp

tasks/swig.rake

@@ -1,5 +1,7 @@
 # frozen-string-literal: true
 
+require_relative 'taglib'
+
 # Tasks for generating SWIG wrappers in ext
 
 # Execute SWIG for the specified extension.
@@ -13,22 +15,23 @@ def run_swig(mod)
   swig = `which swig2.0`.chomp if swig.empty?
 
   # Standard search location for headers
-  include_args = %w[-I/usr/local/include -I/usr/include]
+  include_args = "-I#{Taglib.install_dir}/include"
 
   if ENV.key?('TAGLIB_DIR')
     unless File.directory?(ENV['TAGLIB_DIR'])
       abort 'When defined, the TAGLIB_DIR environment variable must point to a valid directory.'
     end
 
     # Push it in front to get it searched first.
-    include_args.unshift("-I#{ENV['TAGLIB_DIR']}/include")
+    include_args = "-I#{ENV['TAGLIB_DIR']}/include"
   end
 
-  sh "cd ext/#{mod} && #{swig} -c++ -ruby -autorename -initname #{mod} #{include_args.join(' ')} #{mod}.i"
+  sh "cd ext/#{mod} && #{swig} -c++ -ruby -autorename -initname #{mod} #{include_args} #{mod}.i"
 end
 
 task swig:
-  ['ext/taglib_base/taglib_base_wrap.cxx',
+  [Taglib.library,
+   'ext/taglib_base/taglib_base_wrap.cxx',
    'ext/taglib_mpeg/taglib_mpeg_wrap.cxx',
    'ext/taglib_id3v1/taglib_id3v1_wrap.cxx',
    'ext/taglib_id3v2/taglib_id3v2_wrap.cxx',

tasks/taglib.rb

@@ -0,0 +1,37 @@
+# frozen-string-literal: true
+
+class Taglib
+  class << self
+    def plat
+      ENV['PLATFORM'] || 'i386-mingw32'
+    end
+
+    def version
+      ENV['TAGLIB_VERSION'] || '1.9.1'
+    end
+
+    def dir
+      "taglib-#{version}"
+    end
+
+    def tmp
+      "#{__dir__}/../tmp"
+    end
+
+    def source
+      "#{tmp}/#{dir}"
+    end
+
+    def tmp_arch
+      "#{tmp}/#{plat}"
+    end
+
+    def install_dir
+      "#{tmp_arch}/#{dir}"
+    end
+
+    def library
+      "#{install_dir}/lib/libtag.#{RbConfig::CONFIG['SOEXT']}"
+    end
+  end
+end