Implement visualise_cyclic_deps

Author: shreyasbharath

README.md

@@ -74,6 +74,18 @@ Here's a component include dependency visualisation generated for the `queue` co
 
 ![Queue include graph d3](examples/rethinkdb_queue_include_d3.svg)
 
+### Cyclic dependencies only graph
+
+This will highlight cyclic dependencies between components within a project. This is especially useful for targeted refactoring activities to reduce coupling between components.
+
+`cpp_dependency_graph visualise_cyclic_deps -r spec\test\example_project\`
+
+Here's the cyclic dependencies only visualisation generated for [rethinkdb](https://github.com/rethinkdb/rethinkdb) and [leveldb](https://github.com/google/leveldb)
+
+![rethinkdb](examples/rethinkdb_cyclic_deps.svg)
+
+![leveldb](examples/leveldb_cyclic_deps.svg)
+
 ## Development
 
 `bundle exec cpp_dependency_graph visualise -r <dir>`

TODO.md

@@ -3,8 +3,8 @@
 - [ ] Documentation
   - [ ] Screencast of how to use tool on projects
   - [ ] Create a github.io homepage
+  - [ ] Add interactive `html` or `svg` examples to homepage
   - [ ] Add a [CONTRIBUTING.md](https://github.com/nayafia/contributing-template/blob/master/CONTRIBUTING-template.md)
-  - [ ] Add interactive `html` or `svg` examples into README, is this possible?
 - [ ] Progress messages
   - [ ] Progress bar?
 - [x] Allow user to specify a single component and the tool should print only that component
@@ -13,6 +13,7 @@
   - [ ] Manual scanning does not work when #includes are #ifdefed out for example
   - [ ] <system> include vs "project" include (how will this work for third party sources that are not part of the codebase?)
   - [ ] Work with any type of include relative includes ('blah.h') vs absolute includes ('/path/blah.h') vs relative with path includes ('blah/blah.h')
+  - [ ] Look at https://github.com/Sarcasm/compdb to see if it can generate dependencies
 - [ ] Parallelise dependency scanning as much as possible to get the best possible performance
 - [ ] Open up the graph automatically after generating an individual graph
 - [ ] Work with any sort of project structure

examples/leveldb_cyclic_deps.svg

@@ -58,13 +58,13 @@ begin
     Kernel.exit(0)
   end
 
-  unless File.directory?(args['--root_dir'])
+  project_dir = args['--root_dir'].gsub(/\\/,'/')
+
+  unless File.directory?(project_dir)
     puts('Not a valid project source directory')
     Kernel.exit(1)
   end
 
-  project_dir = args['--root_dir'].gsub(/\\/,'/')
-
   if args['visualise']
     if args['--component']
       generate_component_graph(project_dir, args['--component'], args['--output_format'], args['--output_file'])
@@ -76,7 +76,7 @@ begin
   elsif args['visualise_components']
     # TODO: Output components
   elsif args['visualise_cyclic_deps']
-    output_cyclic_dependencies(project_dir)
+    generate_cyclic_dependencies(project_dir, args['--output_format'], args['--output_file'])
   end
 rescue Docopt::Exit => e
   puts e.message

examples/rethinkdb_cyclic_deps.svg

@@ -29,12 +29,11 @@ def generate_component_include_graph(project_dir, component_name, format, output
     generate_visualisation(deps, format, output_file)
   end
 
-  def output_cyclic_dependencies(project_dir)
+  def generate_cyclic_dependencies(project_dir, format, file)
     project = Project.new(project_dir)
     graph = DependencyGraph.new(project)
-    deps = graph.all_component_links
-    cyclic_deps = deps.values.flatten.select { |dep| dep.cyclic? }
-    puts JSON.pretty_generate(cyclic_deps)
+    deps = graph.all_cyclic_links
+    generate_visualisation(deps, format, file)
   end
 
   def generate_visualisation(deps, format, file)
@@ -43,6 +42,8 @@ def generate_visualisation(deps, format, file)
       GraphVisualiser.new.generate_dot_file(deps, file)
     when 'html'
       GraphVisualiser.new.generate_html_file(deps, file)
+    when 'json'
+      File.write(file, JSON.pretty_generate(deps))
     end
   end
 end

exe/cpp_dependency_graph

@@ -21,6 +21,15 @@ def cyclic?
     @cyclic
   end
 
+  def ==(other)
+    (source == other.source && target == other.target && cyclic? == other.cyclic?) ||
+    (source == other.target && target == other.source && cyclic? == other.cyclic?)
+  end
+
+  def hash
+    [source, target, cyclic?].to_set.hash
+  end
+
   def to_s
     if cyclic?
       "#{source} <-> #{target}"

lib/cpp_dependency_graph.rb

@@ -18,6 +18,10 @@ def all_component_links
     @all_component_links ||= build_hash_component_links
   end
 
+  def all_cyclic_links
+    @cyclic_links ||= build_cyclic_links
+  end
+
   def component_links(name)
     return {} unless all_component_links.key?(name)
     incoming_links(name).merge(outgoing_links(name))
@@ -35,6 +39,11 @@ def build_hash_component_links
     component_links
   end
 
+  def build_cyclic_links
+    cyclic_links = all_component_links.select { |_, links| links.any? { |link| link.cyclic? } }
+    cyclic_links.each { |_, links| links.select! { |link| link.cyclic? } }
+  end
+
   def outgoing_links(name)
     all_component_links.slice(name)
   end

lib/cpp_dependency_graph/component_link.rb

@@ -16,4 +16,16 @@
   it 'returns correct cyclic? attribute' do
     expect(ComponentLink.new('source', 'target', true).cyclic?).to eq(true)
   end
+
+  it 'returns equal if another instance has same attributes' do
+    c1 = ComponentLink.new('source', 'target', true)
+    c2 = ComponentLink.new('target', 'source', true)
+    expect(c1). to eq(c2)
+  end
+
+  it 'returns not equal if another instance has different attributes' do
+    c1 = ComponentLink.new('source1', 'target1', true)
+    c2 = ComponentLink.new('source2', 'target2', true)
+    expect(c1).to_not eq(c2)
+  end
 end

lib/cpp_dependency_graph/dependency_graph.rb

@@ -8,4 +8,13 @@
   it 'returns the same hash for two equivalent objects with the same nodes' do
     expect(CyclicLink.new('nodeA', 'nodeB').hash).to eq(CyclicLink.new('nodeB', 'nodeA').hash)
   end
+
+  it 'implements eql? operator correctly for usage as a hash key' do
+    h = {}
+    c1 = CyclicLink.new('nodeA', 'nodeB')
+    c2 = CyclicLink.new('nodeB', 'nodeA')
+    h[c1] = true
+    h[c2] = false
+    expect(h[c1]).to eq(false)
+  end
 end

spec/test/component_link_spec.rb

@@ -0,0 +1,37 @@
+require 'cpp_dependency_graph/dependency_graph'
+require 'cpp_dependency_graph/component_link'
+
+RSpec.describe DependencyGraph do
+  let(:project) { Project.new('spec/test/example_project') }
+  let(:dependency_graph) { DependencyGraph.new(project) }
+
+  it 'returns all links for a project' do
+    expected_links = {}
+    expected_links['UI'] = [ComponentLink.new('UI', 'Framework', false),
+                  ComponentLink.new('UI', 'Engine', true)]
+    expected_links['DataAccess'] = [ComponentLink.new('DataAccess', 'Framework', false)]
+    expected_links['main'] = [ComponentLink.new('main', 'UI', false)]
+    expected_links['Framework'] = []
+    expected_links['System'] = []
+    expected_links['Engine'] = [ComponentLink.new('Engine', 'Framework', false),
+                      ComponentLink.new('Engine', 'UI', true),
+                      ComponentLink.new('Engine', 'DataAccess', false)]
+    expect(dependency_graph.all_component_links).to eq(expected_links)
+  end
+
+  it 'returns links for a specified component of a project' do
+    expected_links = {}
+    expected_links['UI'] = [ComponentLink.new('UI', 'Engine', false)]   # TODO
+    expected_links['Engine'] = [ComponentLink.new('Engine', 'Framework', false),
+                      ComponentLink.new('Engine', 'UI', true),
+                      ComponentLink.new('Engine', 'DataAccess', false)]
+    expect(dependency_graph.component_links('Engine')).to eq(expected_links)
+  end
+
+  it 'returns all cyclic links of a project' do
+    expected_links = {}
+    expected_links['Engine'] = [ComponentLink.new('Engine', 'UI', true)]
+    expected_links['UI'] = [ComponentLink.new('UI', 'Engine', true)]
+    expect(dependency_graph.all_cyclic_links).to eq(expected_links)
+  end
+end