Ruby code generator for C++.

Not yet in active use yet but two sample templates are provided.

Note: same dependency story as java codegen: distribution has pre-generated
code so ruby not required to build a distro. Only required for svn working
copy builds.


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@561468 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 208 insertions, 0 deletions

diff --git a/cpp/rubygen/amqpgen.rb b/cpp/rubygen/amqpgen.rb
new file mode 100755
index 0000000000..3fc66525d8
--- /dev/null
+++ b/cpp/rubygen/amqpgen.rb
@@ -0,0 +1,208 @@
+#
+# Generic AMQP code generation library.
+#
+
+require 'delegate'
+require 'rexml/document'
+require 'pathname'
+include REXML
+
+# Handy String functions for converting names.
+class String
+  # Convert to CapitalizedForm.
+  def caps() gsub( /(^|\W)(\w)/ ) { |m| $2.upcase } end
+
+  # Convert to underbar_separated_form.
+  def bars() tr('- .','_'); end
+
+  # Convert to lowerCaseCapitalizedForm
+  def lcaps() gsub( /\W(\w)/ ) { |m| $1.upcase } end
+end
+
+# Sort an array by name.
+class Array
+  def sort_by_name()
+    sort() { |a,b| a.name <=> b.name }
+  end
+end
+
+# Add collect to Elements
+class Elements
+  def collect(xpath, &block)
+    result=[]
+    each(xpath) { |el| result << yield(el) }
+    result
+  end
+end
+
+# An AmqpElement extends (delegates to) a REXML::Element
+# 
+# NB: AmqpElements cache various values, they assume that
+# the XML model does not change after the AmqpElement has
+# been created.
+# 
+class AmqpElement < DelegateClass(Element)
+  def initialize(xml, amqp) super(xml); @amqp_parent=amqp; end
+
+  attr_reader :amqp_parent
+
+  # Return the name attribute, not the element name.
+  def name() attributes["name"]; end
+
+  def amqp_root()
+    amqp_parent ? amqp_parent.amqp_root : self;
+  end
+end
+
+# AMQP field element
+class AmqpField < AmqpElement
+  def initialize(xml, amqp) super; end;
+
+  # Get AMQP type for a domain name.
+  def domain_type(name)
+    domain=elements["/amqp/domain[@name='#{name}']"]
+    (domain and domain.attributes["type"] or name)
+  end
+
+  # Get the AMQP type of this field.
+  def field_type()
+    d=attributes["domain"]
+    dt=domain_type d if d
+    (dt or attributes["type"])
+  end
+end
+
+# AMQP method element
+class AmqpMethod < AmqpElement
+  def initialize(xml, amqp) super; end
+
+  def fields()
+    @cache_fields ||= elements.collect("field") { |f| AmqpField.new(f,self); }
+  end
+
+  # Responses to this method (0-9)
+  def responses()
+    @cache_responses ||= elements.collect("response") { |el| new AmqpMethod(el,self) }
+  end
+
+  # Methods this method responds to (0-9)
+  def responds_to()
+    @cache_responds_to ||= elements.collect("../method/response[@name='#{attributes['name']}']") { |el|
+      AmqpMethod.new(el.parent, amqp_parent)
+    }
+  end
+
+  def request?() responds_to().empty?; end
+  def response?() not request?; end
+end
+
+# AMQP class element.
+class AmqpClass < AmqpElement
+  def initialize(xml,amqp) super; end
+
+  def methods()
+    @cache_methods ||= elements.collect("method") { |el|
+      AmqpMethod.new(el,self)
+    }.sort_by_name
+  end
+
+  # chassis should be "client" or "server"
+  def methods_on(chassis)
+    elements.collect("method/chassis[@name='#{chassis}']/..") { |m|
+      AmqpMethod.new(m,self)
+    }.sort_by_name
+  end
+end
+
+# AMQP root element.
+class AmqpRoot < AmqpElement
+
+  # Initialize with output directory and spec files from ARGV.
+  def initialize(*specs)
+    specs.size or raise "No XML spec files."
+    specs.each { |f| File.exists?(f) or raise "Invalid XML file: #{f}"}
+    super Document.new(File.new(specs.shift)).root, nil
+    specs.each { |s|            # Merge in additional specs
+      root=Document.new(File.new(s)).root
+      merge(self,root)
+    }
+  end
+
+  def version()
+    attributes["major"]+"-"+attributes["minor"]
+  end
+
+  def classes()
+    @cache_classes ||= elements.collect("class") { |c| AmqpClass.new(c,self) }.sort_by_name
+  end
+
+  # Return all methods on chassis for all classes.
+  def methods_on(chassis)
+    classes.collect { |c|
+      c.methods_on(chassis)
+    }.flatten
+  end
+
+  # Merge contents of elements.
+  def merge(to,from)
+    from.elements.each { |from_child|
+      tag,name = from_child.name, from_child.attributes["name"]
+      to_child=to.elements["./#{tag}[@name='#{name}']"]
+      to_child ? merge(to_child, from_child) : to.add(from_child.clone) }
+  end
+
+  private :merge
+  
+end
+
+# Base class for code generators.
+# Supports setting a per-line prefix, useful for e.g. indenting code.
+# 
+class Generator
+  # Takes directory for output or "-", meaning print file names that
+  # would be generated.
+  def initialize (outdir, amqp)
+    @amqp=amqp
+    @outdir=outdir
+    @prefix=''                  # For indentation or comments.
+    @indentstr='    '           # One indent level.
+    raise "Invalid output directory: #{outdir}" unless @outdir=="-" or File.directory?(@outdir) 
+  end
+
+  # Create a new file, set @out. 
+  def file(file)
+    puts file                   
+    if (@outdir != "-")         
+      path=Pathname.new "#{@outdir}/#{file}"
+      path.parent.mkpath
+      path.open('w') { |@out| yield }
+    end
+  end
+
+  # Append multi-line string to generated code, prefixing each line.
+  def gen (str)
+    str.each_line { |line|
+      @out << @prefix unless @midline
+      @out << line
+      @midline = nil
+    }
+    # Note if we stopped mid-line
+    @midline = /[^\n]\z/ === str
+  end
+
+  # Generate code with added prefix.
+  def prefix(add)
+    save=@prefix
+    @prefix+=add
+    yield
+    @prefix=save
+  end
+  
+  # Generate indented code
+  def indent(n=1,&block) prefix(@indentstr * n,&block); end
+
+  attr_accessor :out
+end
+
+
+