Refactored formatters and updated the the writers a bit.

- Formatters have been abstracted similarly to readers and writers now.
 - The Ascii writer has a new option for writing out logs as JSON.
 - The Ascii writer now has all options availble as per-filter
   options as well as global.

src/threading/formatters/JSON.cc

@@ -0,0 +1,177 @@
+// See the file "COPYING" in the main distribution directory for copyright.
+
+#include "config.h"
+
+#include <sstream>
+#include <errno.h>
+
+#include "./JSON.h"
+
+using namespace threading::formatter;
+
+JSON::JSON(MsgThread* t) : Formatter(t)
+	{
+	}
+
+JSON::~JSON()
+	{
+	}
+
+bool JSON::Describe(ODesc* desc, int num_fields, const Field* const * fields,
+                    Value** vals) const
+	{
+	desc->AddRaw("{");
+	for ( int i = 0; i < num_fields; i++ )
+		{
+		if ( i > 0 &&
+		     desc->Bytes()[desc->Len()] != ',' && vals[i]->present )
+			{
+			desc->AddRaw(",");
+			}
+
+		if ( ! Describe(desc, vals[i], fields[i]->name) )
+			return false;
+		}
+	desc->AddRaw("}");
+	return true;
+	}
+
+bool JSON::Describe(ODesc* desc, Value* val, const string& name) const
+	{
+	if ( ! val->present )
+		return true;
+
+	desc->AddRaw("\"", 1);
+	desc->Add(name);
+	desc->AddRaw("\":", 2);
+
+	return Describe(desc, val);
+	}
+
+bool JSON::Describe(ODesc* desc, Value* val) const
+	{
+	if ( ! val->present )
+		return true;
+
+	switch ( val->type )
+		{
+		case TYPE_BOOL:
+			desc->AddRaw(val->val.int_val == 0 ? "false" : "true");
+			break;
+
+		case TYPE_INT:
+			desc->Add(val->val.int_val);
+			break;
+
+		case TYPE_COUNT:
+		case TYPE_COUNTER:
+			{
+			// JSON doesn't support unsigned 64bit ints.
+			if ( val->val.uint_val >= INT64_MAX )
+				{
+				thread->Error(thread->Fmt("count value too large for JSON: %" PRIu64, val->val.uint_val));
+				desc->AddRaw("null", 4);
+				}
+			else
+				desc->Add(val->val.uint_val);
+			break;
+			}
+
+		case TYPE_PORT:
+			desc->Add(val->val.port_val.port);
+			break;
+
+		case TYPE_SUBNET:
+			desc->AddRaw("\"", 1);
+			desc->Add(Render(val->val.subnet_val));
+			desc->AddRaw("\"", 1);
+			break;
+
+		case TYPE_ADDR:
+			desc->AddRaw("\"", 1);
+			desc->Add(Render(val->val.addr_val));
+			desc->AddRaw("\"", 1);
+			break;
+
+		case TYPE_DOUBLE:
+		case TYPE_INTERVAL:
+			desc->Add(val->val.double_val);
+			break;
+
+		case TYPE_TIME:
+			{
+			// ElasticSearch uses milliseconds for timestamps and json only
+			// supports signed ints (uints can be too large).
+			uint64_t ts = (uint64_t) (val->val.double_val * 1000);
+			if ( ts >= INT64_MAX )
+				{
+				thread->Error(thread->Fmt("time value too large for JSON: %" PRIu64, ts));
+				desc->AddRaw("null", 4);
+				}
+			else
+				desc->Add(ts);
+			break;
+			}
+
+		case TYPE_ENUM:
+		case TYPE_STRING:
+		case TYPE_FILE:
+		case TYPE_FUNC:
+			{
+			desc->AddRaw("\"", 1);
+			for ( int i = 0; i < val->val.string_val.length; ++i )
+				{
+				char c = val->val.string_val.data[i];
+				// 2byte Unicode escape special characters.
+				if ( c < 32 || c > 126 || c == '\n' || c == '"' || c == '\'' || c == '\\' || c == '&' )
+					{
+					static const char hex_chars[] = "0123456789abcdef";
+					desc->AddRaw("\\u00", 4);
+					desc->AddRaw(&hex_chars[(c & 0xf0) >> 4], 1);
+					desc->AddRaw(&hex_chars[c & 0x0f], 1);
+					}
+				else
+					desc->AddRaw(&c, 1);
+				}
+			desc->AddRaw("\"", 1);
+			break;
+			}
+
+		case TYPE_TABLE:
+			{
+			desc->AddRaw("[", 1);
+			for ( int j = 0; j < val->val.set_val.size; j++ )
+				{
+				if ( j > 0 )
+					desc->AddRaw(",", 1);
+				Describe(desc, val->val.set_val.vals[j]);
+				}
+			desc->AddRaw("]", 1);
+			break;
+			}
+
+		case TYPE_VECTOR:
+			{
+			desc->AddRaw("[", 1);
+			for ( int j = 0; j < val->val.vector_val.size; j++ )
+				{
+				if ( j > 0 )
+					desc->AddRaw(",", 1);
+				Describe(desc, val->val.vector_val.vals[j]);
+				}
+			desc->AddRaw("]", 1);
+			break;
+			}
+
+		default:
+			return false;
+		}
+
+	return true;
+	}
+
+threading::Value* JSON::ParseValue(string s, string name, TypeTag type, TypeTag subtype) const
+	{
+	thread->Error("JSON formatter does not support parsing yet.");
+	return NULL;
+	}