1 files changed, 65 insertions, 0 deletions
diff --git a/tool/checksum.rb b/tool/checksum.rb
new file mode 100755
index 0000000000..40f444efd2
--- /dev/null
+++ b/tool/checksum.rb
@@ -0,0 +1,65 @@
+#!ruby
+
+require_relative 'vpath'
+
+class Checksum
+  def initialize(vpath)
+    @vpath = vpath
+  end
+
+  def source=(source)
+    @source = source
+    @checksum = File.basename(source, ".*") + ".chksum"
+  end
+
+  def update?
+    src = @vpath.read(@source)
+    @len = src.length
+    @sum = src.sum
+    begin
+      data = @vpath.read(@checksum)
+    rescue
+      return false
+    else
+      return false unless data[/src="([0-9a-z_.-]+)",/, 1] == @source
+      return false unless @len == data[/\blen=(\d+)/, 1].to_i
+      return false unless @sum == data[/\bchecksum=(\d+)/, 1].to_i
+      return true
+    end
+  end
+
+  def update!
+    open(@checksum, "wb") {|f|
+      f.puts("src=\"#{@source}\", len=#{@len}, checksum=#{@sum}")
+    }
+  end
+
+  def update
+    return true if update?
+    update! if ret = yield(self)
+    ret
+  end
+
+  def copy(name)
+    @vpath.open(name, "rb") {|f|
+      IO.copy_stream(f, name)
+    }
+    true
+  end
+
+  def make(arg)
+    system([@make, arg].compact.join(' '))
+  end
+
+  def def_options(opt = (require 'optparse'; OptionParser.new))
+    @vpath.def_options(opt)
+    opt.on("--make=PATH") {|v| @make = v}
+    opt
+  end
+
+  def self.update(argv)
+    k = new(VPath.new)
+    k.source, *argv = k.def_options.parse(*argv)
+    k.update {|k| yield(k, *argv)}
+  end
+end