Implement JSONHandler for recursively processing JSON

1 files changed, 128 insertions, 0 deletions

diff --git a/libtests/json_handler.cc b/libtests/json_handler.cc
new file mode 100644
index 00000000..d5e6aea3
--- /dev/null
+++ b/libtests/json_handler.cc
@@ -0,0 +1,128 @@
+#include <qpdf/JSONHandler.hh>
+#include <qpdf/QUtil.hh>
+#include <iostream>
+#include <cassert>
+
+static void print_null(std::string const& path)
+{
+    std::cout << path << ": null" << std::endl;
+}
+
+static void print_string(std::string const& path, std::string const& value)
+{
+    std::cout << path << ": string: " << value << std::endl;
+}
+
+static void print_number(std::string const& path, std::string const& value)
+{
+    std::cout << path << ": number: " << value << std::endl;
+}
+
+static void print_bool(std::string const& path, bool value)
+{
+    std::cout << path << ": bool: " << (value ? "true" : "false") << std::endl;
+}
+
+static void print_json(std::string const& path, JSON value)
+{
+    std::cout << path << ": json: " << value.unparse() << std::endl;
+}
+
+static void test_scalar()
+{
+    std::cout << "-- scalar --" << std::endl;
+    JSONHandler h;
+    h.addStringHandler(print_string);
+    JSON j = JSON::parse("\"potato\"");
+    h.handle(".", j);
+}
+
+static std::shared_ptr<JSONHandler> make_all_handler()
+{
+    auto h = std::make_shared<JSONHandler>();
+    auto& m = h->addDictHandlers();
+    auto h1 = std::make_shared<JSONHandler>();
+    h1->addStringHandler(print_string);
+    m["one"] = h1;
+    auto h2 = std::make_shared<JSONHandler>();
+    h2->addNumberHandler(print_number);
+    m["two"] = h2;
+    auto h3 = std::make_shared<JSONHandler>();
+    h3->addBoolHandler(print_bool);
+    m["three"] = h3;
+    auto h4 = std::make_shared<JSONHandler>();
+    h4->addAnyHandler(print_json);
+    m["four"] = h4;
+    m["phour"] = h4;           // share h4
+    auto h5 = std::make_shared<JSONHandler>();
+    // Allow to be either string or bool
+    h5->addBoolHandler(print_bool);
+    h5->addStringHandler(print_string);
+    h5->addNullHandler(print_null);
+    auto h5s = std::make_shared<JSONHandler>();
+    m["five"] = h5s;
+    h5s->addArrayHandler(h5);
+    auto h6 = std::make_shared<JSONHandler>();
+    auto& m6 = h6->addDictHandlers();
+    auto h6a = std::make_shared<JSONHandler>();
+    m6["a"] = h6a;
+    auto& m6a = h6a->addDictHandlers();
+    auto h6ab = std::make_shared<JSONHandler>();
+    m6a["b"] = h6ab;
+    auto h6ax = std::make_shared<JSONHandler>();
+    h6ax->addAnyHandler(print_json);
+    h6a->addFallbackDictHandler(h6ax);
+    m6["b"] = h6ab;             // share
+    h6ab->addStringHandler(print_string);
+    m["six"] = h6;
+    return h;
+}
+
+static void test_all()
+{
+    std::cout << "-- all --" << std::endl;
+    auto h = make_all_handler();
+    JSON j = JSON::parse(R"({
+   "one": "potato",
+   "two": 3.14,
+   "three": true,
+   "four": ["a", 1],
+   "five": ["x", false, "y", null, true],
+   "phour": null,
+   "six": {"a": {"b": "quack", "Q": "baaa"}, "b": "moo"}
+})");
+    h->handle(".", j);
+}
+
+static void test_errors()
+{
+    std::cout << "-- errors --" << std::endl;
+    auto h = make_all_handler();
+    auto t = [h](std::string const& msg, std::function<void()> fn) {
+        try
+        {
+            fn();
+            assert(false);
+        }
+        catch (JSONHandler::Error& e)
+        {
+            std::cout << msg << ": " << e.what() << std::endl;
+        }
+    };
+
+    t("bad type at top", [&h](){
+        h->handle(".", JSON::makeString("oops"));
+    });
+    t("unexpected key", [&h](){
+        JSON j = JSON::parse(R"({"x": "y"})");
+        h->handle(".", j);
+    });
+}
+
+int main(int argc, char* argv[])
+{
+    test_scalar();
+    test_all();
+    test_errors();
+    return 0;
+}