Implement JSONHandler for recursively processing JSON

6 files changed, 208 insertions, 1 deletions

diff --git a/libtests/build.mk b/libtests/build.mk
index a23b9c28..682c2b6d 100644
--- a/libtests/build.mk
+++ b/libtests/build.mk
@@ -13,6 +13,7 @@ BINS_libtests = \
 	hex \
 	input_source \
 	json \
+	json_handler \
 	json_parse \
 	lzw \
 	main_from_wmain \
diff --git a/libtests/json.cc b/libtests/json.cc
index 7bea5589..006f00cf 100644
--- a/libtests/json.cc
+++ b/libtests/json.cc
@@ -1,7 +1,7 @@
 #include <qpdf/JSON.hh>
 #include <qpdf/QPDFObjectHandle.hh>
 #include <iostream>
-#include <assert.h>
+#include <cassert>
 
 static void check(JSON const& j, std::string const& exp)
 {
@@ -20,12 +20,25 @@ static void test_main()
           "\\u0003\\t\\b\\r\\n<4>\"");
     JSON jnull = JSON::makeNull();
     check(jnull, "null");
+    assert(jnull.isNull());
+    std::string value;
+    assert(! jnull.getNumber(value));
     JSON jarr = JSON::makeArray();
     check(jarr, "[]");
     JSON jstr2 = JSON::makeString("a\tb");
+    assert(jstr2.getString(value));
+    assert(value == "a\tb");
+    assert(! jstr2.getNumber(value));
     JSON jint = JSON::makeInt(16059);
     JSON jdouble = JSON::makeReal(3.14159);
     JSON jexp = JSON::makeNumber("2.1e5");
+    JSON jbool1 = JSON::makeBool(true);
+    JSON jbool2 = JSON::makeBool(false);
+    bool bvalue = false;
+    assert(jbool1.getBool(bvalue));
+    assert(bvalue);
+    assert(jbool2.getBool(bvalue));
+    assert(! bvalue);
     jarr.addArrayElement(jstr2);
     jarr.addArrayElement(jnull);
     jarr.addArrayElement(jint);
@@ -39,6 +52,18 @@ static void test_main()
           "  3.14159,\n"
           "  2.1e5\n"
           "]");
+    std::vector<std::string> avalue;
+    assert(jarr.forEachArrayItem([&avalue](JSON j) {
+        avalue.push_back(j.unparse());
+    }));
+    std::vector<std::string> xavalue = {
+        "\"a\\tb\"",
+        "null",
+        "16059",
+        "3.14159",
+        "2.1e5",
+    };
+    assert(avalue == xavalue);
     JSON jmap = JSON::makeDictionary();
     check(jmap, "{}");
     jmap.addDictionaryMember("b", jstr2);
@@ -73,6 +98,18 @@ static void test_main()
     check(QPDFObjectHandle::newReal(".34").getJSON(), "0.34");
     check(QPDFObjectHandle::newReal("-0.56").getJSON(), "-0.56");
     check(QPDFObjectHandle::newReal("-.78").getJSON(), "-0.78");
+    JSON jmap2 = JSON::parse(R"({"a": 1, "b": "two", "c": [true]})");
+    std::map<std::string, std::string> dvalue;
+    assert(jmap2.forEachDictItem([&dvalue]
+                                 (std::string const& k, JSON j) {
+        dvalue[k] = j.unparse();
+    }));
+    std::map<std::string, std::string> xdvalue = {
+        {"a", "1"},
+        {"b", "\"two\""},
+        {"c", "[\n  true\n]"},
+    };
+    assert(dvalue == xdvalue);
 }
 
 static void check_schema(JSON& obj, JSON& schema, bool exp,
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;
+}
diff --git a/libtests/libtests.testcov b/libtests/libtests.testcov
index 5f36819a..6284c0e8 100644
--- a/libtests/libtests.testcov
+++ b/libtests/libtests.testcov
@@ -87,3 +87,5 @@ JSON parse leading zero 0
 JSON parse number no digits 0
 JSON parse premature end of u 0
 JSON parse bad hex after u 0
+JSONHandler unhandled value 0
+JSONHandler unexpected key 0
diff --git a/libtests/qtest/json_handler.test b/libtests/qtest/json_handler.test
new file mode 100644
index 00000000..6df51fc1
--- /dev/null
+++ b/libtests/qtest/json_handler.test
@@ -0,0 +1,17 @@
+#!/usr/bin/env perl
+require 5.008;
+use warnings;
+use strict;
+
+chdir("json_handler") or die "chdir testdir failed: $!\n";
+
+require TestDriver;
+
+my $td = new TestDriver('json_handler');
+
+$td->runtest("JSON handler",
+             {$td->COMMAND => "json_handler"},
+             {$td->FILE => "json_handler.out", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+
+$td->report(1);
diff --git a/libtests/qtest/json_handler/json_handler.out b/libtests/qtest/json_handler/json_handler.out
new file mode 100644
index 00000000..13554af3
--- /dev/null
+++ b/libtests/qtest/json_handler/json_handler.out
@@ -0,0 +1,22 @@
+-- scalar --
+.: string: potato
+-- all --
+.five[0]: string: x
+.five[1]: bool: false
+.five[2]: string: y
+.five[3]: null
+.five[4]: bool: true
+.four: json: [
+  "a",
+  1
+]
+.one: string: potato
+.phour: json: null
+.six.a.Q: json: "baaa"
+.six.a.b: string: quack
+.six.b: string: moo
+.three: bool: true
+.two: number: 3.14
+-- errors --
+bad type at top: JSON handler: value at . is not of expected type
+unexpected key: JSON handler found unexpected key x in object at .