Add FFI JavaScript as a webpack dependency

Resolves #18

3 files changed, 79 insertions, 3 deletions

diff --git a/src/FS.purs b/src/FS.purs
index a56fe26..6955a63 100644
--- a/src/FS.purs
+++ b/src/FS.purs
@@ -1,12 +1,16 @@
 module PursLoader.FS
   ( FS()
   , writeFileUtf8
+  , findFileUtf8
   ) where
 
 import Control.Monad.Aff (Aff(), makeAff)
 import Control.Monad.Eff (Eff())
 import Control.Monad.Eff.Exception (Error())
 
+import Data.Maybe (Maybe(..))
+import Data.String.Regex (Regex())
+
 import Data.Function
 
 foreign import data FS :: !
@@ -30,3 +34,34 @@ function writeFileUtf8Fn(filepath, contents, errback, callback) {
                        (Error -> Eff (fs :: FS | eff) Unit)
                        (Unit -> Eff (fs :: FS | eff) Unit)
                        (Eff (fs :: FS | eff) Unit)
+
+findFileUtf8 :: forall eff. Regex -> [String] -> Aff (fs :: FS | eff) (Maybe String)
+findFileUtf8 regexp filepaths = makeAff $ runFn6 findFileUtf8Fn Nothing Just regexp filepaths
+
+foreign import findFileUtf8Fn """
+function findFileUtf8Fn(nothing, just, regex, filepaths, errback, callback) {
+  return function(){
+    var fs = require('fs');
+
+    var async = require('async');
+
+    function findFile(filepath, callback) {
+      fs.readFile(filepath, {encoding: 'utf-8'}, function(error, result){
+        if (error) callback(false);
+        else callback(regex.test(result));
+      });
+    }
+
+    async.detect(filepaths, findFile, function(result){
+      if (!result) callback(nothing)();
+      else callback(just(result))();
+    });
+  };
+}
+""" :: forall eff. Fn6 (Maybe String)
+                       (String -> Maybe String)
+                       Regex
+                       [String]
+                       (Error -> Eff (fs :: FS | eff) Unit)
+                       (Maybe String -> Eff (fs :: FS | eff) Unit)
+                       (Eff (fs :: FS | eff) Unit)
diff --git a/src/Loader.purs b/src/Loader.purs
index 872a51c..e9e03c4 100644
--- a/src/Loader.purs
+++ b/src/Loader.purs
@@ -13,12 +13,12 @@ import Data.Array ((!!), concat)
 import Data.Function (Fn2(), mkFn2)
 import Data.Maybe (Maybe(..), fromMaybe, maybe)
 import Data.String (joinWith)
-import Data.String.Regex (match, noFlags, regex)
+import Data.String.Regex (match, noFlags, regex, test)
 
 import PursLoader.ChildProcess (ChildProcess(), spawn)
-import PursLoader.FS (FS(), writeFileUtf8)
+import PursLoader.FS (FS(), writeFileUtf8, findFileUtf8)
 import PursLoader.Glob (Glob(), globAll)
-import PursLoader.LoaderRef (LoaderRef(), Loader(), async, cacheable, query)
+import PursLoader.LoaderRef (LoaderRef(), Loader(), async, cacheable, query, clearDependencies, addDependency, resourcePath)
 import PursLoader.LoaderUtil (parseQuery)
 import PursLoader.Options (loaderFFIOption, loaderSrcOption, pscOptions)
 
@@ -26,6 +26,8 @@ type Effects eff = (cp :: ChildProcess, fs :: FS, glob :: Glob, loader :: Loader
 
 moduleRegex = regex "(?:^|\\n)module\\s+([\\w\\.]+)" noFlags { ignoreCase = true }
 
+foreignRegex = regex "(?:^|\\n)\\s*foreign import\\s+" noFlags { ignoreCase = true }
+
 pscCommand = "psc"
 
 psciCommand = "psci"
@@ -54,6 +56,11 @@ mkPsci srcs ffis = joinWith "\n" ((loadModule <$> concat srcs) <> (loadForeign <
     loadForeign :: String -> String
     loadForeign a = ":f " ++ relative cwd a
 
+findFFI :: forall eff. [[String]] -> String -> Aff (fs :: FS | eff) (Maybe String)
+findFFI ffiss name = findFileUtf8 re (concat ffiss)
+  where
+    re = regex ("(?:^|\\n)//\\s*module\\s*" ++ name ++ "\\s*\\n") noFlags
+
 loader' :: forall eff. LoaderRef -> String -> Aff (Effects eff) (Maybe String)
 loader' ref source = do
   liftEff $ cacheable ref
@@ -73,8 +80,18 @@ loader' ref source = do
   writeFileUtf8 psciFilename psciFile
 
   let moduleName = match moduleRegex source >>= (!!!) 1
+      hasForeign = test foreignRegex source
       result = (\a -> "module.exports = require('" ++ a ++ "');") <$> moduleName
 
+  liftEff (clearDependencies ref)
+  liftEff (addDependency ref (resourcePath ref))
+
+  foreignPath <- if hasForeign
+                    then fromMaybe (pure Nothing) (findFFI ffiss <$> moduleName)
+                    else pure Nothing
+
+  fromMaybe (pure unit) ((\path -> liftEff (addDependency ref path)) <$> foreignPath)
+
   return result
 
 loader :: forall eff. LoaderRef -> String -> Eff (Effects eff) Unit
diff --git a/src/LoaderRef.purs b/src/LoaderRef.purs
index 2567b1e..f1efa04 100644
--- a/src/LoaderRef.purs
+++ b/src/LoaderRef.purs
@@ -4,6 +4,9 @@ module PursLoader.LoaderRef
   , async
   , cacheable
   , query
+  , clearDependencies
+  , addDependency
+  , resourcePath
   ) where
 
 import Control.Monad.Eff (Eff())
@@ -48,3 +51,24 @@ foreign import query """
 function query(ref){
   return ref.query;
 }""" :: LoaderRef -> String
+
+foreign import clearDependencies """
+function clearDependencies(ref){
+  return function(){
+    return ref.clearDependencies();
+  };
+}""" :: forall eff. LoaderRef -> Eff (loader :: Loader | eff) Unit
+
+foreign import resourcePath """
+function resourcePath(ref){
+  return ref.resourcePath;
+}""" :: LoaderRef -> String
+
+foreign import addDependency """
+function addDependency(ref){
+  return function(dep){
+    return function(){
+      return ref.addDependency(dep);
+    };
+  };
+}""" :: forall eff. LoaderRef -> String -> Eff (loader :: Loader | eff) Unit