Merge pull request #2381 from monaka/pr-add-include_paths-in-dependency-gems

Append include paths in dependency gems

2 files changed, 42 insertions, 4 deletions

diff --git a/doc/mrbgems/README.md b/doc/mrbgems/README.md
index 7ac225730..571c00450 100644
--- a/doc/mrbgems/README.md
+++ b/doc/mrbgems/README.md
@@ -76,6 +76,8 @@ The maximal GEM structure looks like this:
 
 	+- GEM_NAME         <- Name of GEM
 	   |
+	   +- include/      <- Header for Ruby extension (will exported)
+	   |
 	   +- mrblib/       <- Source for Ruby extension
 	   |
 	   +- src/          <- Source for C extension
@@ -87,10 +89,10 @@ The maximal GEM structure looks like this:
 	   +- README.md     <- Readme for GEM
 
 The folder *mrblib* contains pure Ruby files to extend mruby. The folder *src*
-contains C files to extend mruby. The folder *test* contains C and pure Ruby files
-for testing purposes which will be used by `mrbtest`. *mrbgem.rake* contains
-the specification to compile C and Ruby files. *README.md* is a short description
-of your GEM.
+contains C/C++ files to extend mruby. The folder *include* contains C/C++ header
+files. The folder *test* contains C/C++ and pure Ruby files for testing purposes
+which will be used by `mrbtest`. *mrbgem.rake* contains the specification
+to compile C and Ruby files. *README.md* is a short description of your GEM.
 
 ## Build process
 
@@ -173,6 +175,19 @@ the following options additionally inside of your GEM specification:
 * `spec.test_objs` (Object test files for integration into mrbtest)
 * `spec.test_preload` (Initialization files for mrbtest)
 
+### include_paths and depencency
+
+Your GEM can export include paths to another GEMs that depends on your GEM.
+By default, `/...absolute path.../{GEM_NAME}/include` will be exported.
+So it is recommended not to put GEM's local header files on include/.
+
+These exports are retroactive.
+For example: when B depends to C and A depends to B, A will get include paths exported by C.
+
+Exported include_paths are automatically appended to GEM local include_paths by Minirake.
+You can use `spec.export_include_paths` accessor if you want more complex build.
+
+
 ## C Extension
 
 mruby can be extended with C. This is possible by using the C API to
diff --git a/tasks/mrbgem_spec.rake b/tasks/mrbgem_spec.rake
index 09e000a4a..c8868fe9c 100644
--- a/tasks/mrbgem_spec.rake
+++ b/tasks/mrbgem_spec.rake
@@ -34,6 +34,8 @@ module MRuby
       attr_accessor :requirements
       attr_reader :dependencies
 
+      attr_accessor :export_include_paths
+
       attr_block MRuby::Build::COMMANDS
 
       def initialize(name, &block)
@@ -71,6 +73,8 @@ module MRuby
 
         @requirements = []
         @dependencies = []
+        @export_include_paths = []
+        @export_include_paths << "#{dir}/include" if File.directory? "#{dir}/include"
 
         instance_eval(&@initializer)
 
@@ -336,6 +340,25 @@ module MRuby
         rescue TSort::Cyclic => e
           fail "Circular mrbgem dependency found: #{e.message}"
         end
+
+        each do |g|
+          import_include_paths(g)
+        end
+      end
+
+      def import_include_paths(g)
+        gem_table = @ary.reduce({}) { |res,v| res[v.name] = v; res }
+        g.dependencies.each do |dep|
+          dep_g = gem_table[dep[:gem]]
+          # We can do recursive call safely
+          # as circular dependency has already detected in the caller.
+          import_include_paths(dep_g)
+
+          g.compilers.each do |compiler|
+            compiler.include_paths += dep_g.export_include_paths
+            g.export_include_paths += dep_g.export_include_paths
+          end
+        end
       end
     end # List
   end # Gem