Hoist selectors in feature queries

ast.hpp

@@ -345,9 +345,10 @@ namespace Sass {
   ///////////////////
   class Feature_Block : public Has_Block {
     ADD_PROPERTY(Feature_Queries*, feature_queries);
+    ADD_PROPERTY(Selector*, selector);
   public:
     Feature_Block(string path, Position position, Feature_Queries* fqs, Block* b)
-    : Has_Block(path, position, b), feature_queries_(fqs)
+    : Has_Block(path, position, b), feature_queries_(fqs), selector_(0)
     { }
     bool is_hoistable() { return true; }
     ATTACH_OPERATIONS();

expand.cpp

@@ -95,6 +95,7 @@ namespace Sass {
                                                     f->position(),
                                                     static_cast<Feature_Queries*>(feature_queries),
                                                     f->block()->perform(this)->block());
+    ff->selector(selector_stack.back());
     return ff;
   }
 

extend.cpp

@@ -1939,6 +1939,10 @@ namespace Sass {
 
   void Extend::operator()(Feature_Block* pFeatureBlock)
   {
+    if (pFeatureBlock->selector()) {
+      extendObjectWithSelectorAndBlock(pFeatureBlock, ctx, subset_map);
+    }
+
     pFeatureBlock->block()->perform(this);
   }
 

output_nested.cpp

@@ -124,6 +124,82 @@ namespace Sass {
     }
   }
 
+  void Output_Nested::operator()(Feature_Block* f)
+  {
+    Feature_Queries*  q = f->feature_queries();
+    Block* b            = f->block();
+
+    // Filter out feature blocks that aren't printable (process its children though)
+    if (!Util::isPrintable(f)) {
+      for (size_t i = 0, L = b->length(); i < L; ++i) {
+        Statement* stm = (*b)[i];
+        if (dynamic_cast<Has_Block*>(stm)) {
+          stm->perform(this);
+        }
+      }
+      return;
+    }
+
+    indent();
+    ctx->source_map.add_mapping(f);
+    append_to_buffer("@supports ");
+    q->perform(this);
+    append_to_buffer(" {\n");
+
+    Selector* e = f->selector();
+    if (e && b->has_non_hoistable()) {
+      // JMA - hoisted, output the non-hoistable in a nested block, followed by the hoistable
+      ++indentation;
+      indent();
+      e->perform(this);
+      append_to_buffer(" {\n");
+
+      ++indentation;
+      for (size_t i = 0, L = b->length(); i < L; ++i) {
+        Statement* stm = (*b)[i];
+        if (!stm->is_hoistable()) {
+          if (!stm->block()) indent();
+          stm->perform(this);
+          append_to_buffer("\n");
+        }
+      }
+      --indentation;
+
+      buffer.erase(buffer.length()-1);
+      if (ctx) ctx->source_map.remove_line();
+      append_to_buffer(" }\n");
+      --indentation;
+
+      ++indentation;
+      ++indentation;
+      for (size_t i = 0, L = b->length(); i < L; ++i) {
+        Statement* stm = (*b)[i];
+        if (stm->is_hoistable()) {
+          stm->perform(this);
+        }
+      }
+      --indentation;
+      --indentation;
+    }
+    else {
+      // JMA - not hoisted, just output in order
+      ++indentation;
+      for (size_t i = 0, L = b->length(); i < L; ++i) {
+        Statement* stm = (*b)[i];
+        if (!stm->is_hoistable()) {
+          if (!stm->block()) indent();
+        }
+        stm->perform(this);
+        append_to_buffer("\n");
+      }
+      --indentation;
+    }
+
+    buffer.erase(buffer.length()-1);
+    if (ctx) ctx->source_map.remove_line();
+    append_to_buffer(" }\n");
+  }
+
   void Output_Nested::operator()(Media_Block* m)
   {
     List*  q     = m->media_queries();
@@ -139,7 +215,7 @@ namespace Sass {
       }
       return;
     }
-    
+
     indent();
     ctx->source_map.add_mapping(m);
     append_to_buffer("@media ");
@@ -153,7 +229,7 @@ namespace Sass {
       indent();
       e->perform(this);
       append_to_buffer(" {\n");
-      
+
       ++indentation;
       for (size_t i = 0, L = b->length(); i < L; ++i) {
         Statement* stm = (*b)[i];
@@ -164,12 +240,12 @@ namespace Sass {
         }
       }
       --indentation;
-      
+
       buffer.erase(buffer.length()-1);
       if (ctx) ctx->source_map.remove_line();
       append_to_buffer(" }\n");
       --indentation;
-      
+
       ++indentation;
       ++indentation;
       for (size_t i = 0, L = b->length(); i < L; ++i) {
@@ -194,7 +270,7 @@ namespace Sass {
       }
       --indentation;
     }
-    
+
     buffer.erase(buffer.length()-1);
     if (ctx) ctx->source_map.remove_line();
     append_to_buffer(" }\n");

output_nested.hpp

@@ -43,6 +43,7 @@ namespace Sass {
     virtual void operator()(Block*);
     virtual void operator()(Ruleset*);
     // virtual void operator()(Propset*);
+    virtual void operator()(Feature_Block*);
     virtual void operator()(Media_Block*);
     virtual void operator()(At_Rule*);
     // virtual void operator()(Declaration*);

util.cpp

@@ -55,12 +55,13 @@ namespace Sass {
 
       Block* b = f->block();
 
-      bool hasSelectors = false;
+      bool hasSelectors = f->selector() && static_cast<Selector_List*>(f->selector())->length() > 0;
+
       bool hasDeclarations = false;
       bool hasPrintableChildBlocks = false;
       for (size_t i = 0, L = b->length(); i < L; ++i) {
         Statement* stm = (*b)[i];
-        if (!stm->is_hoistable() && !hasSelectors) {
+        if (!stm->is_hoistable() && f->selector() != NULL && !hasSelectors) {
           // If a statement isn't hoistable, the selectors apply to it. If there are no selectors (a selector list of length 0),
           // then those statements aren't considered printable. That means there was a placeholder that was removed. If the selector
           // is NULL, then that means there was never a wrapping selector and it is printable (think of a top level media block with