From cdb1a73615415e88ac8ef1b2eeec216fe72b9794 Mon Sep 17 00:00:00 2001
From: "Yichun Zhang (agentzh)" <agentzh@gmail.com>
Date: Tue, 18 Feb 2014 14:33:37 -0800
Subject: feature: applied Jiale Zhi's patch to add the new config function
 encode_empty_table_as_object so that we can encode empty Lua tables into
 empty JSON arrays.

---
 lua_cjson.c      | 14 +++++++++++-
 tests/TestLua.pm | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/agentzh.t  | 41 +++++++++++++++++++++++++++++++++
 3 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100644 tests/TestLua.pm
 create mode 100644 tests/agentzh.t

diff --git a/lua_cjson.c b/lua_cjson.c
index c14a1c5..97f2350 100644
--- a/lua_cjson.c
+++ b/lua_cjson.c
@@ -68,6 +68,7 @@
 #define DEFAULT_DECODE_INVALID_NUMBERS 1
 #define DEFAULT_ENCODE_KEEP_BUFFER 1
 #define DEFAULT_ENCODE_NUMBER_PRECISION 14
+#define DEFAULT_ENCODE_EMPTY_TABLE_AS_OBJECT 1
 
 #ifdef DISABLE_INVALID_NUMBERS
 #undef DEFAULT_DECODE_INVALID_NUMBERS
@@ -124,6 +125,7 @@ typedef struct {
     int encode_invalid_numbers;     /* 2 => Encode as "null" */
     int encode_number_precision;
     int encode_keep_buffer;
+    int encode_empty_table_as_object;
 
     int decode_invalid_numbers;
     int decode_max_depth;
@@ -300,6 +302,14 @@ static int json_cfg_encode_number_precision(lua_State *l)
     return json_integer_option(l, 1, &cfg->encode_number_precision, 1, 14);
 }
 
+/* Configures how to treat empty table when encode lua table */
+static int json_cfg_encode_empty_table_as_object(lua_State *l)
+{
+    json_config_t *cfg = json_arg_init(l, 1);
+
+    return json_enum_option(l, 1, &cfg->encode_empty_table_as_object, NULL, 1);
+}
+
 /* Configures JSON encoding buffer persistence */
 static int json_cfg_encode_keep_buffer(lua_State *l)
 {
@@ -390,6 +400,7 @@ static void json_create_config(lua_State *l)
     cfg->decode_invalid_numbers = DEFAULT_DECODE_INVALID_NUMBERS;
     cfg->encode_keep_buffer = DEFAULT_ENCODE_KEEP_BUFFER;
     cfg->encode_number_precision = DEFAULT_ENCODE_NUMBER_PRECISION;
+    cfg->encode_empty_table_as_object = DEFAULT_ENCODE_EMPTY_TABLE_AS_OBJECT;
 
 #if DEFAULT_ENCODE_KEEP_BUFFER > 0
     strbuf_init(&cfg->encode_buf, 0);
@@ -685,7 +696,7 @@ static void json_append_data(lua_State *l, json_config_t *cfg,
         current_depth++;
         json_check_encode_depth(l, cfg, current_depth, json);
         len = lua_array_length(l, cfg, json);
-        if (len > 0)
+        if (len > 0 || (len == 0 && !cfg->encode_empty_table_as_object))
             json_append_array(l, cfg, current_depth, json, len);
         else
             json_append_object(l, cfg, current_depth, json);
@@ -1352,6 +1363,7 @@ static int lua_cjson_new(lua_State *l)
     luaL_Reg reg[] = {
         { "encode", json_encode },
         { "decode", json_decode },
+        { "encode_empty_table_as_object", json_cfg_encode_empty_table_as_object },
         { "encode_sparse_array", json_cfg_encode_sparse_array },
         { "encode_max_depth", json_cfg_encode_max_depth },
         { "decode_max_depth", json_cfg_decode_max_depth },
diff --git a/tests/TestLua.pm b/tests/TestLua.pm
new file mode 100644
index 0000000..cd22d83
--- /dev/null
+++ b/tests/TestLua.pm
@@ -0,0 +1,70 @@
+package TestLua;
+
+use Test::Base -Base;
+use IPC::Run3;
+use Cwd;
+
+use Test::LongString;
+
+our @EXPORT = qw( run_tests );
+
+$ENV{LUA_CPATH} = "../?.so;;";
+$ENV{LUA_PATH} = "../lua/?.lua;;";
+#$ENV{LUA_PATH} = ($ENV{LUA_PATH} || "" ) . ';' . getcwd . "/runtime/?.lua" . ';;';
+
+sub run_test ($) {
+    my $block = shift;
+    #print $json_xs->pretty->encode(\@new_rows);
+    #my $res = #print $json_xs->pretty->encode($res);
+    my $name = $block->name;
+
+    my $lua = $block->lua or
+        die "No --- lua specified for test $name\n";
+
+    my $luafile = "test_case.lua";
+
+    open my $fh, ">$luafile" or
+        die "Cannot open $luafile for writing: $!\n";
+
+    print $fh $lua;
+    close $fh;
+
+    my ($res, $err);
+
+    my @cmd;
+
+    if ($ENV{TEST_LUA_USE_VALGRIND}) {
+        @cmd =  ('valgrind', '-q', '--leak-check=full', 'lua', 'test_case.lua');
+    } else {
+        @cmd =  ('lua', 'test_case.lua');
+    }
+
+    run3 \@cmd, undef, \$res, \$err;
+    my $rc = $?;
+
+    #warn "res:$res\nerr:$err\n";
+
+    if (defined $block->err) {
+        $err =~ /.*:.*:.*: (.*\s)?/;
+        $err = $1;
+        is $err, $block->err, "$name - err expected";
+
+    } elsif ($rc) {
+        die "Failed to execute --- lua for test $name: $err\n";
+
+    } else {
+        #is $res, $block->out, "$name - output ok";
+        is $res, $block->out, "$name - output ok";
+    }
+
+    is $rc, ($block->exit || 0), "$name - exit code ok";
+    #unlink 'test_case.lua' or warn "could not delete \'test_case.lua\':$!";
+}
+
+sub run_tests () {
+    for my $block (blocks()) {
+        run_test($block);
+    }
+}
+
+1;
diff --git a/tests/agentzh.t b/tests/agentzh.t
new file mode 100644
index 0000000..aeebd67
--- /dev/null
+++ b/tests/agentzh.t
@@ -0,0 +1,41 @@
+use TestLua;
+
+plan tests => 2 * blocks();
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: empty tables as objects
+--- lua
+local cjson = require "cjson"
+print(cjson.encode({}))
+print(cjson.encode({dogs = {}}))
+--- out
+{}
+{"dogs":{}}
+
+
+
+=== TEST 2: empty tables as arrays
+--- lua
+local cjson = require "cjson"
+cjson.encode_empty_table_as_object(false)
+print(cjson.encode({}))
+print(cjson.encode({dogs = {}}))
+--- out
+[]
+{"dogs":[]}
+
+
+
+=== TEST 3: empty tables as objects (explicit)
+--- lua
+local cjson = require "cjson"
+cjson.encode_empty_table_as_object(true)
+print(cjson.encode({}))
+print(cjson.encode({dogs = {}}))
+--- out
+{}
+{"dogs":{}}
+
-- 
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