Add initial version

5 files changed, 227 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
@@ -0,0 +1 @@
+*~
diff --git a/README.org b/README.org
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+++ b/README.org
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+#+TILTE: dotdot
+#+SUBTITLE: Programmatic dotfile manager
+
+* Synopsis
+=dotdot= was born as a dotfile manager (though it could be used for many purposes). Fundamentally, its job is:
+1. to evaluate a recipe describing e.g. how to set up =~/=,
+2. check if the recipe can be executed safely, e.g. that there are no files that would be overwritten, that all necessary directories exist,
+3. execute the recipe.
+* Usage
+Currently, =dotdot= is only intended for my personal use, so I haven’t taken time to document it or even rigorously test it.  =dotdot= is provided /as is/, and currently you must read the code to understand how it works.
+
+I intend to write documentation for it someday, but it’s too currently too early for that.
diff --git a/core.rb b/core.rb
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+++ b/core.rb
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+class Op
+  def check
+    raise "#{self.class} doesn't have a (required) 'check' method"
+  end
+  def do
+    raise "#{self.class} doesn't have a (required) 'do' method"
+  end
+  def undo
+    raise "#{self.class} doesn't have a (required) 'undo' method"
+  end
+end
+
+def defop(name, args, &block)
+  name = name.to_sym
+  eval "class #{name} < Op; end"  # Must use `eval' to access
+  cls = eval "#{name}"            # the global namespace
+  cls.instance_eval do
+    args.map {|a| attr_reader a.to_sym }
+  end
+  cls.define_method :initialize do |**kwargs|
+    args.each {|arg| instance_variable_set :"@#{arg}", kwargs[arg.to_sym] }
+  end
+  cls.define_method :to_s do inspect end
+  cls.define_method :to_str do to_s end
+  cls.instance_eval &block
+end
+
+defop :Write, [:file, :contents] do
+  define_method :check do
+    if File.exist? @file
+      if (File.read @file) != @contents
+        raise "File `#{@file}' exists but has unexpected contents"
+      else true
+      end
+    end
+  end
+  define_method :do do
+    write @file, @contents
+  end
+  define_method :undo do
+    rm @file
+  end
+end
+
+defop :Deploy, [:ops, :save] do
+  define_method :initialize do |save: nil, &block|
+    @ops = []
+    @save = save
+    self.instance_eval &block
+  end
+  define_method :check do
+    @ops.all? {|op| op.check } and
+      (@save ? self.save.check : true)
+  end
+  define_method :do do
+    self.load.undo if @save && self.save.check
+    @ops.each {|op| op.check || op.do }
+    self.save.do if @save
+  end
+  define_method :undo do
+    @ops.reverse.each {|op| op.check && op.undo }
+    self.save.undo if @save
+  end
+  define_method :save do
+    (Write.new file: @save,
+               contents: self.to_yaml)
+  end
+  define_method :load do
+    YAML.load_file(
+      @save,
+      permitted_classes: ([Op] + Op.subclasses))
+  end
+end
+
+def deploy(...)
+  Deploy.new(...)
+end
+
+def defdeploy(name, &block)
+  Deploy.define_method name, &block
+end
+
+defdeploy :op do |cls, **args|
+  @ops.push cls.new(**args)
+end
diff --git a/dotdot b/dotdot
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+++ b/dotdot
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+#!/usr/bin/ruby
+%w[socket fileutils yaml]
+  .map { require _1 }
+
+HOME = ENV["HOME"] or File.expand_path "~/"
+HOSTNAME = Socket.gethostname
+
+class Binding
+  def eval_file(path)
+    self.eval (File.read path)
+  end
+end
+
+def eval_file(file)
+  file = File.expand_path file
+  dir = File.dirname file
+  binding.eval_file file
+end
+
+def ls(dir)
+  Dir.entries(dir).reject {|d| [".", ".."].include? d }
+end
+
+def ln(from, to)
+  FileUtils.ln_s from, to
+end
+
+def write(file, contents)
+  File.write file, contents
+end
+
+def rm(file)
+  FileUtils.rm file
+end
+
+def mkdir(dir)
+  FileUtils.mkdir_p dir
+end
+
+def rmdir(dir)
+  FileUtils.rmdir dir
+end
+
+require_relative "core"
+require_relative "stdlib"
+
+$cmds = {
+  show: lambda {|op|
+    if op.is_a? Deploy
+      puts op.ops
+    else
+      puts op
+    end
+  },
+  debug: lambda {|op|
+    puts op.to_yaml
+  },
+  check: lambda {|op|
+    if op.check
+      puts "nothing left to do"
+    else
+      puts "not fully deployed"
+    end
+  },
+  do: lambda {|op| op.do },
+  undo: lambda {|op| op.undo },
+}
+def main
+  command = ARGV.shift.to_sym
+  file = ARGV.shift || "#{HOSTNAME}.rb"
+  op = eval_file file
+  $cmds[command][op]
+end
+
+main if __FILE__ == $0
diff --git a/stdlib.rb b/stdlib.rb
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+++ b/stdlib.rb
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+defop :MkDir, [:dir] do
+  define_method :check do
+    File.directory? @dir
+  end
+  define_method :do do
+    mkdir @dir
+  end
+  define_method :undo do
+    rmdir @dir if File.exist? @dir and Dir.empty? @dir
+  end
+  define_method :inspect do
+    "#<MkDir '#{@dir}'>"
+  end
+end
+
+defop :SymLink, [:from, :to] do
+  define_method :check do
+    if File.exist? @to or File.symlink? @to  # broken symlink should be kept
+      if !(File.symlink? @to) or (File.readlink @to) != @from
+        raise "File '#{@to}' exists but is not a symlink to '#{@from}'"
+      else true
+      end
+    end
+  end
+  define_method :do do
+    ln @from, @to
+  end
+  define_method :undo do
+    rm @to
+  end
+  define_method :inspect do
+    "#<SymLink '#{@from}' -> '#{to}>"
+  end
+end
+
+defdeploy :tree do |src:, dst:, ignores: [/~$/], stops: []|
+  sp, dp = [src, dst].map {|p| File.expand_path p }
+  src = lambda {|path| File.join sp, path }
+  dst = lambda {|path| File.join dp, path }
+  recur = lambda do |path|
+    return if ignores.any? {|pat| path =~ pat }
+    if File.directory?(src[path])
+      if stops.include? path
+        op SymLink, from: src[path], to: dst[path]
+      else
+        op MkDir, dir: dst[path]
+        (ls src[path]).each {|p| recur[File.join path, p] }
+      end
+    else
+      op SymLink, from: src[path], to: dst[path]
+    end
+  end
+  (ls sp).each {|path| recur[path] }
+end