Create Download Strategy sooner in formula install code.

* Instantiate DownloadStrategy instance when creating a formula.
* Rename CurlDownloadStrategy member to clarify what it is for.
* Generate downloaded tarball name in initialize.

Library/Homebrew/download_strategy.rb

@@ -53,42 +53,46 @@ class AbstractDownloadStrategy
 end
 
 class CurlDownloadStrategy <AbstractDownloadStrategy
+  def initialize url, name, version, specs
+    super
+    if @unique_token
+      @tarball_path=HOMEBREW_CACHE+(@unique_token+ext)
+    else
+      @tarball_path=HOMEBREW_CACHE+File.basename(@url)
+    end
+  end
+  
   def fetch
     ohai "Downloading #{@url}"
-    if @unique_token
+    unless @tarball_path.exist?
-      @dl=HOMEBREW_CACHE+(@unique_token+ext)
-    else
-      @dl=HOMEBREW_CACHE+File.basename(@url)
-    end
-    unless @dl.exist?
       begin
-        curl @url, '-o', @dl
+        curl @url, '-o', @tarball_path
       rescue Exception
-        ignore_interrupts { @dl.unlink if @dl.exist? }
+        ignore_interrupts { @tarball_path.unlink if @tarball_path.exist? }
         raise
       end
     else
       puts "File already downloaded and cached to #{HOMEBREW_CACHE}"
     end
-    return @dl # thus performs checksum verification
+    return @tarball_path # thus performs checksum verification
   end
 
   def stage
-    # magic numbers stolen from /usr/share/file/magic/
+    if @tarball_path.extname == '.jar'
-    if @dl.extname == '.jar'
       magic_bytes = nil
     else
       # get the first four bytes
-      File.open(@dl) { |f| magic_bytes = f.read(4) }
+      File.open(@tarball_path) { |f| magic_bytes = f.read(4) }
     end
 
+    # magic numbers stolen from /usr/share/file/magic/
     case magic_bytes
     when /^PK\003\004/ # .zip archive
-      quiet_safe_system '/usr/bin/unzip', {:quiet_flag => '-qq'}, @dl
+      quiet_safe_system '/usr/bin/unzip', {:quiet_flag => '-qq'}, @tarball_path
       chdir
     when /^\037\213/, /^BZh/, /^\037\235/  # gzip/bz2/compress compressed
       # TODO check if it's really a tar archive
-      safe_system '/usr/bin/tar', 'xf', @dl
+      safe_system '/usr/bin/tar', 'xf', @tarball_path
       chdir
     else
       # we are assuming it is not an archive, use original filename
@@ -98,7 +102,7 @@ class CurlDownloadStrategy <AbstractDownloadStrategy
       # behaviour, just open an issue at github
       # We also do this for jar files, as they are in fact zip files, but
       # we don't want to unzip them
-      FileUtils.mv @dl, File.basename(@url)
+      FileUtils.mv @tarball_path, File.basename(@url)
     end
   end
 
@@ -130,7 +134,7 @@ end
 # Useful for installing jars.
 class NoUnzipCurlDownloadStrategy <CurlDownloadStrategy
   def stage
-    FileUtils.mv @dl, File.basename(@url)
+    FileUtils.mv @tarball_path, File.basename(@url)
   end
 end
 

Library/Homebrew/formula.rb

@@ -112,6 +112,8 @@ class Formula
     CHECKSUM_TYPES.each do |type|
       set_instance_variable type
     end
+
+    @downloader=download_strategy.new url, name, version, specs
   end
 
   # if the dir is there, but it's empty we consider it not installed
@@ -365,12 +367,15 @@ private
   end
 
   def stage
-    ds=download_strategy.new url, name, version, specs
     HOMEBREW_CACHE.mkpath
-    dl=ds.fetch
+
-    verify_download_integrity dl if dl.kind_of? Pathname
+    downloaded_tarball = @downloader.fetch
+    if downloaded_tarball.kind_of? Pathname
+      verify_download_integrity downloaded_tarball
+    end
+  
     mktemp do
-      ds.stage
+      @downloader.stage
       yield
     end
   end