Fold SkJSON into Skia/utils

It's a tiny, core-ish component -- might as well treat as such to
simplify dependencies.

Change-Id: I6f31ce2d151f9a629d88bfc7f15d64891d5150c0
Reviewed-on: https://skia-review.googlesource.com/135780
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/tests/JSONTest.cpp b/tests/JSONTest.cpp
new file mode 100644
index 0000000..72c71e3
--- /dev/null
+++ b/tests/JSONTest.cpp
@@ -0,0 +1,388 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+
+#include "SkArenaAlloc.h"
+#include "SkJSON.h"
+#include "SkString.h"
+#include "SkStream.h"
+
+using namespace skjson;
+
+DEF_TEST(JSON_Parse, reporter) {
+    static constexpr struct {
+        const char* in;
+        const char* out;
+    } g_tests[] = {
+        { ""     , nullptr },
+        { "["    , nullptr },
+        { "]"    , nullptr },
+        { "[[]"  , nullptr },
+        { "[]]"  , nullptr },
+        { "[]f"  , nullptr },
+        { "{"    , nullptr },
+        { "}"    , nullptr },
+        { "{{}"  , nullptr },
+        { "{}}"  , nullptr },
+        { "{}f"  , nullptr },
+        { "{]"   , nullptr },
+        { "[}"   , nullptr },
+        { "{\"}" , nullptr },
+        { "[\"]" , nullptr },
+        { "1"    , nullptr },
+        { "true" , nullptr },
+        { "false", nullptr },
+        { "null" , nullptr },
+
+        { "[nulll]" , nullptr },
+        { "[false2]", nullptr },
+        { "[true:]" , nullptr },
+
+        { "[1 2]"   , nullptr },
+        { "[1,,2]"  , nullptr },
+        { "[1,2,]"  , nullptr },
+        { "[,1,2]"  , nullptr },
+
+        { "[ \"foo"       , nullptr },
+        { "[ \"fo\0o\" ]" , nullptr },
+
+        { "{\"\":{}"                  , nullptr },
+        { "{ null }"                  , nullptr },
+        { "{ \"k\" : }"               , nullptr },
+        { "{ : null }"                , nullptr },
+        { "{ \"k\" : : null }"        , nullptr },
+        { "{ \"k\" : null , }"        , nullptr },
+        { "{ \"k\" : null \"k\" : 1 }", nullptr },
+
+
+        { "[]"                           , "[]" },
+        { " \n\r\t [ \n\r\t ] \n\r\t "   , "[]" },
+        { "[[]]"                         , "[[]]" },
+        { "[ null ]"                     , "[null]" },
+        { "[ true ]"                     , "[true]" },
+        { "[ false ]"                    , "[false]" },
+        { "[ 0 ]"                        , "[0]" },
+        { "[ 1 ]"                        , "[1]" },
+        { "[ 1.248 ]"                    , "[1.248]" },
+        { "[ \"\" ]"                     , "[\"\"]" },
+        { "[ \"foo{bar}baz\" ]"          , "[\"foo{bar}baz\"]" },
+        { "[ \" f o o \" ]"              , "[\" f o o \"]" },
+        { "[ \"123456\" ]"               , "[\"123456\"]" },
+        { "[ \"1234567\" ]"              , "[\"1234567\"]" },
+        { "[ \"12345678\" ]"             , "[\"12345678\"]" },
+        { "[ \"123456789\" ]"            , "[\"123456789\"]" },
+        { "[ null , true, false,0,12.8 ]", "[null,true,false,0,12.8]" },
+
+        { "{}"                          , "{}" },
+        { " \n\r\t { \n\r\t } \n\r\t "  , "{}" },
+        { "{ \"k\" : null }"            , "{\"k\":null}" },
+        { "{ \"foo{\" : \"bar}baz\" }"  , "{\"foo{\":\"bar}baz\"}" },
+        { "{ \"k1\" : null, \"k2 \":0 }", "{\"k1\":null,\"k2 \":0}" },
+        { "{ \"k1\" : null, \"k1\":0 }" , "{\"k1\":null,\"k1\":0}" },
+
+        { "{ \"k1\" : null,                   \n\
+             \"k2\" : 0,                      \n\
+             \"k3\" : [                       \n\
+                        true,                 \r\n\
+                        { \"kk1\" : \"foo\" , \n\
+                          \"kk2\" : \"bar\" , \n\
+                          \"kk3\" : 1.28 ,    \n\
+                          \"kk4\" : [ 42 ]    \n\
+                        } ,                   \n\
+                        \"boo\" ,             \n\
+                        null                  \n\
+                      ]                       \n\
+           }",
+          "{\"k1\":null,\"k2\":0,\"k3\":[true,"
+              "{\"kk1\":\"foo\",\"kk2\":\"bar\",\"kk3\":1.28,\"kk4\":[42]},\"boo\",null]}" },
+    };
+
+    for (const auto& tst : g_tests) {
+        DOM dom(tst.in, strlen(tst.in));
+        const auto success = !dom.root().is<NullValue>();
+        REPORTER_ASSERT(reporter, success == (tst.out != nullptr));
+        if (!success) continue;
+
+        SkDynamicMemoryWStream str;
+        dom.write(&str);
+        str.write8('\0');
+
+        auto data = str.detachAsData();
+        REPORTER_ASSERT(reporter, !strcmp(tst.out, static_cast<const char*>(data->data())));
+    }
+
+}
+
+template <typename T, typename VT>
+static void check_primitive(skiatest::Reporter* reporter, const Value& v, T pv,
+                            bool is_type) {
+
+    REPORTER_ASSERT(reporter,  v.is<VT>() == is_type);
+    const VT* cast_t = v;
+    REPORTER_ASSERT(reporter, (cast_t != nullptr) == is_type);
+
+    if (is_type) {
+        REPORTER_ASSERT(reporter, &v.as<VT>() == cast_t);
+        REPORTER_ASSERT(reporter, *v.as<VT>() == pv);
+    }
+}
+
+template <typename T>
+static void check_vector(skiatest::Reporter* reporter, const Value& v, size_t expected_size,
+                         bool is_vector) {
+    REPORTER_ASSERT(reporter, v.is<T>() == is_vector);
+    const T* cast_t = v;
+    REPORTER_ASSERT(reporter, (cast_t != nullptr) == is_vector);
+
+    if (is_vector) {
+        const auto& vec = v.as<T>();
+        REPORTER_ASSERT(reporter, &vec == cast_t);
+        REPORTER_ASSERT(reporter, vec.size()  == expected_size);
+        REPORTER_ASSERT(reporter, vec.begin() != nullptr);
+        REPORTER_ASSERT(reporter, vec.end()   == vec.begin() + expected_size);
+    }
+}
+
+static void check_string(skiatest::Reporter* reporter, const Value& v, const char* s) {
+    check_vector<StringValue>(reporter, v, s ? strlen(s) : 0, !!s);
+    if (s) {
+        REPORTER_ASSERT(reporter, !strcmp(v.as<StringValue>().begin(), s));
+    }
+}
+
+DEF_TEST(JSON_DOM_visit, reporter) {
+    static constexpr char json[] = "{ \n\
+        \"k1\": null,                \n\
+        \"k2\": false,               \n\
+        \"k3\": true,                \n\
+        \"k4\": 42,                  \n\
+        \"k5\": .75,                 \n\
+        \"k6\": \"foo\",             \n\
+        \"k7\": [ 1, true, \"bar\" ], \n\
+        \"k8\": { \"kk1\": 2, \"kk2\": false, \"kk1\": \"baz\" } \n\
+    }";
+
+    DOM dom(json, strlen(json));
+
+    const auto& jroot = dom.root().as<ObjectValue>();
+    REPORTER_ASSERT(reporter, jroot.is<ObjectValue>());
+
+    {
+        const auto& v = jroot["k1"];
+        REPORTER_ASSERT(reporter,  v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k2"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, true);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k3"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, true, true);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k4"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, 42, true);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k5"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, .75f, true);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k6"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, "foo");
+        check_vector<ArrayValue >(reporter, v, 0, false);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+    }
+
+    {
+        const auto& v = jroot["k7"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ObjectValue>(reporter, v, 0, false);
+
+        check_vector<ArrayValue >(reporter, v, 3, true);
+        check_primitive<float, NumberValue>(reporter, v.as<ArrayValue>()[0], 1, true);
+        check_primitive<bool, BoolValue>(reporter, v.as<ArrayValue>()[1], true, true);
+        check_vector<StringValue>(reporter, v.as<ArrayValue>()[2], 3, true);
+    }
+
+    {
+        const auto& v = jroot["k8"];
+        REPORTER_ASSERT(reporter, !v.is<NullValue>());
+
+        check_primitive<bool, BoolValue>(reporter, v, false, false);
+        check_primitive<float, NumberValue>(reporter, v, 0, false);
+
+        check_string(reporter, v, nullptr);
+        check_vector<ArrayValue >(reporter, v, 0, false);
+
+        check_vector<ObjectValue>(reporter, v, 3, true);
+
+        const auto& m0 = v.as<ObjectValue>().begin()[0];
+        check_string(reporter, m0.fKey, "kk1");
+        check_primitive<float, NumberValue>(reporter, m0.fValue, 2, true);
+
+        const auto& m1 = v.as<ObjectValue>().begin()[1];
+        check_string(reporter, m1.fKey, "kk2");
+        check_primitive<bool, BoolValue>(reporter, m1.fValue, false, true);
+
+        const auto& m2 = v.as<ObjectValue>().begin()[2];
+        check_string(reporter, m2.fKey, "kk1");
+        check_string(reporter, m2.fValue, "baz");
+
+        REPORTER_ASSERT(reporter, v.as<ObjectValue>()[""].is<NullValue>());
+        REPORTER_ASSERT(reporter, v.as<ObjectValue>()["nosuchkey"].is<NullValue>());
+        check_string(reporter, v.as<ObjectValue>()["kk1"], "baz");
+        check_primitive<bool, BoolValue>(reporter, v.as<ObjectValue>()["kk2"], false, true);
+    }
+}
+
+template <typename T>
+void check_value(skiatest::Reporter* reporter, const Value& v, const char* expected_string) {
+    REPORTER_ASSERT(reporter, v.is<T>());
+
+    const T* cast_t = v;
+    REPORTER_ASSERT(reporter, cast_t == &v.as<T>());
+
+    const auto vstr = v.toString();
+    REPORTER_ASSERT(reporter, 0 == strcmp(expected_string, vstr.c_str()));
+}
+
+DEF_TEST(JSON_DOM_build, reporter) {
+    SkArenaAlloc alloc(4096);
+
+    const auto v0  = NullValue();
+    check_value<NullValue>(reporter, v0, "null");
+
+    const auto v1  = BoolValue(true);
+    check_value<BoolValue>(reporter, v1, "true");
+
+    const auto v2  = BoolValue(false);
+    check_value<BoolValue>(reporter, v2, "false");
+
+    const auto v3  = NumberValue(0);
+    check_value<NumberValue>(reporter, v3, "0");
+
+    const auto v4  = NumberValue(42);
+    check_value<NumberValue>(reporter, v4, "42");
+
+    const auto v5  = NumberValue(42.75f);
+    check_value<NumberValue>(reporter, v5, "42.75");
+
+    const auto v6  = StringValue(nullptr, 0, alloc);
+    check_value<StringValue>(reporter, v6, "\"\"");
+
+    const auto v7  = StringValue(" foo ", 5, alloc);
+    check_value<StringValue>(reporter, v7, "\" foo \"");
+
+    const auto v8  = StringValue(" foo bar baz ", 13, alloc);
+    check_value<StringValue>(reporter, v8, "\" foo bar baz \"");
+
+    const auto v9  = ArrayValue(nullptr, 0, alloc);
+    check_value<ArrayValue>(reporter, v9, "[]");
+
+    const Value values0[] = { v0, v3, v9 };
+    const auto v10 = ArrayValue(values0, SK_ARRAY_COUNT(values0), alloc);
+    check_value<ArrayValue>(reporter, v10, "[null,0,[]]");
+
+    const auto v11 = ObjectValue(nullptr, 0, alloc);
+    check_value<ObjectValue>(reporter, v11, "{}");
+
+    const Member members0[] = {
+        { StringValue("key_0", 5, alloc), v1  },
+        { StringValue("key_1", 5, alloc), v4  },
+        { StringValue("key_2", 5, alloc), v11 },
+    };
+    const auto v12 = ObjectValue(members0, SK_ARRAY_COUNT(members0), alloc);
+    check_value<ObjectValue>(reporter, v12, "{"
+                                                "\"key_0\":true,"
+                                                "\"key_1\":42,"
+                                                "\"key_2\":{}"
+                                            "}");
+
+    const Value values1[] = { v2, v6, v12 };
+    const auto v13 = ArrayValue(values1, SK_ARRAY_COUNT(values1), alloc);
+    check_value<ArrayValue>(reporter, v13, "["
+                                               "false,"
+                                               "\"\","
+                                               "{"
+                                                   "\"key_0\":true,"
+                                                   "\"key_1\":42,"
+                                                   "\"key_2\":{}"
+                                               "}"
+                                           "]");
+
+    const Member members1[] = {
+        { StringValue("key_00", 6, alloc), v5  },
+        { StringValue("key_01", 6, alloc), v7  },
+        { StringValue("key_02", 6, alloc), v13 },
+    };
+    const auto v14 = ObjectValue(members1, SK_ARRAY_COUNT(members1), alloc);
+    check_value<ObjectValue>(reporter, v14, "{"
+                                                "\"key_00\":42.75,"
+                                                "\"key_01\":\" foo \","
+                                                "\"key_02\":["
+                                                                "false,"
+                                                                "\"\","
+                                                                "{"
+                                                                    "\"key_0\":true,"
+                                                                    "\"key_1\":42,"
+                                                                    "\"key_2\":{}"
+                                                                "}"
+                                                            "]"
+                                            "}");
+}