[examples] add output and combining to multi threaded parse example

examples/integration/multi_threaded.c

@@ -49,15 +49,9 @@ parse_worker_loop(ThreadData *thread_data)
         }
         MD_String8 file_name = MD_S8CString(task->tasks[task_index]);
         MD_ParseResult parse = MD_ParseWholeFile(thread_data->arena, file_name);
-        if (parse.errors.first != 0)
-        {
         MD_MessageListConcat(&thread_data->errors, &parse.errors);
-        }
-        else
-        {
         MD_PushNewReference(thread_data->arena, thread_data->list, parse.node);
     }
-    }
     
     atomic_inc_u64(&task->thread_counter);
 }
@@ -144,5 +138,37 @@ main(int argc, char **argv)
 #endif
     }
     
-    // TODO(allen): combine results
+    // print results
+    for (int i = 0; i < THREAD_COUNT; i += 1)
+    {
+        fprintf(stdout, "on thread %d:\n", i);
+        
+        // print the name of each root
+        for (MD_EachNode(root_it, threads[i].list->first_child))
+        {
+            MD_Node *root = MD_ResolveNodeFromReference(root_it);
+            fprintf(stdout, "%.*s\n", MD_S8VArg(root->string));
+        }
+        
+        // print the errors from this thread
+        MD_MessageList errors = threads[i].errors; 
+        for (MD_Message *message = errors.first;
+             message != 0;
+             message = message->next)
+        {
+            MD_CodeLoc loc = MD_CodeLocFromNode(message->node);
+            MD_PrintMessage(stdout, loc, message->kind, message->string);
+        }
+    }
+    
+    // combine results
+    MD_Arena *arena = threads[0].arena;
+    MD_Node *list = threads[0].list;
+    MD_MessageList errors = threads[0].errors; 
+    for (int i = 1; i < THREAD_COUNT; i += 1)
+    {
+        MD_ArenaDefaultAbsorb(arena, threads[i].arena);
+        MD_ListConcatInPlace(list, threads[i].list);
+        MD_MessageListConcat(&errors, &threads[i].errors);
+    }
 }

source/md.c

@@ -597,7 +597,20 @@ MD_ArenaDefaultSetAutoAlign(MD_ArenaDefault *arena, MD_u64 align)
     arena->align = align;
 }
 
-// TODO(allen): Arena absorb
+static void
+MD_ArenaDefaultAbsorb(MD_ArenaDefault *arena, MD_ArenaDefault *sub_arena)
+{
+    MD_ArenaDefault *current = arena->current;
+    MD_u64 base_pos_shift = current->base_pos + current->cap;
+    for (MD_ArenaDefault *node = sub_arena->current;
+         node != 0;
+         node = node->prev)
+    {
+        node->base_pos += base_pos_shift;
+    }
+    sub_arena->prev = arena->current;
+    arena->current = sub_arena->current;
+}
 
 #endif
 
@@ -2926,9 +2939,9 @@ MD_MessageListPush(MD_MessageList *list, MD_Message *message)
 MD_FUNCTION void
 MD_MessageListConcat(MD_MessageList *list, MD_MessageList *to_push)
 {
-    if(list->last)
-    {
     if(to_push->node_count != 0)
+    {
+        if(list->last != 0)
         {
             list->last->next = to_push->first;
             list->last = to_push->last;
@@ -2938,12 +2951,12 @@ MD_MessageListConcat(MD_MessageList *list, MD_MessageList *to_push)
                 list->max_message_kind = to_push->max_message_kind;
             }
         }
-    }
         else
         {
             *list = *to_push;
         }
         MD_MemoryZeroStruct(to_push);
+    }
 }
 
 //~ Location Conversions
@@ -2996,7 +3009,7 @@ MD_CodeLocFromNode(MD_Node *node)
 MD_FUNCTION MD_b32
 MD_NodeIsNil(MD_Node *node)
 {
-    return node == 0 || node == &_md_nil_node || node->kind == MD_NodeKind_Nil;
+    return(node == 0 || node == &_md_nil_node || node->kind == MD_NodeKind_Nil);
 }
 
 MD_FUNCTION MD_Node *
@@ -3045,6 +3058,25 @@ MD_MakeList(MD_Arena *arena)
     return(result);
 }
 
+MD_FUNCTION void
+MD_ListConcatInPlace(MD_Node *list, MD_Node *to_push)
+{
+    if (!MD_NodeIsNil(to_push->first_child))
+    {
+        if (!MD_NodeIsNil(list->first_child))
+        {
+            list->last_child->next = to_push->first_child;
+            list->last_child = to_push->last_child;
+        }
+        else
+        {
+            list->first_child = to_push->first_child;
+            list->last_child = to_push->last_child;
+        }
+        to_push->first_child = to_push->last_child = MD_NilNode();
+    }
+}
+
 MD_FUNCTION MD_Node*
 MD_PushNewReference(MD_Arena *arena, MD_Node *list, MD_Node *target)
 {

source/md.h

@@ -1085,6 +1085,7 @@ MD_FUNCTION void     MD_PushChild(MD_Node *parent, MD_Node *new_child);
 MD_FUNCTION void     MD_PushTag(MD_Node *node, MD_Node *tag);
 
 MD_FUNCTION MD_Node *MD_MakeList(MD_Arena *arena);
+MD_FUNCTION void     MD_ListConcatInPlace(MD_Node *list, MD_Node *to_push);
 MD_FUNCTION MD_Node *MD_PushNewReference(MD_Arena *arena, MD_Node *list, MD_Node *target);
 
 //~ Introspection Helpers