From a41b7899955a2bf54315fc2507f8e2f010ff271a Mon Sep 17 00:00:00 2001
From: m-holger <m-holger@kubitscheck.org>
Date: Sun, 14 Jan 2024 16:38:51 +0000
Subject: [PATCH] Add new method JSON::getDictItem

---
 include/qpdf/JSON.hh |  2 ++
 libqpdf/JSON.cc      | 11 +++++++++++
 libtests/json.cc     |  6 ++++++
 3 files changed, 19 insertions(+)

diff --git a/include/qpdf/JSON.hh b/include/qpdf/JSON.hh
index 81abe89c..e3c8a7dc 100644
--- a/include/qpdf/JSON.hh
+++ b/include/qpdf/JSON.hh
@@ -162,6 +162,8 @@ class JSON
     QPDF_DLL
     bool isNull() const;
     QPDF_DLL
+    JSON getDictItem(std::string const& key) const;
+    QPDF_DLL
     bool forEachDictItem(std::function<void(std::string const& key, JSON value)> fn) const;
     QPDF_DLL
     bool forEachArrayItem(std::function<void(JSON value)> fn) const;
diff --git a/libqpdf/JSON.cc b/libqpdf/JSON.cc
index f6401642..35b8fd76 100644
--- a/libqpdf/JSON.cc
+++ b/libqpdf/JSON.cc
@@ -410,6 +410,17 @@ JSON::isNull() const
     return m->value->type_code == vt_null;
 }
 
+JSON
+JSON::getDictItem(std::string const& key) const
+{
+    if (auto v = dynamic_cast<JSON_dictionary const*>(m->value.get())) {
+        if (auto it = v->members.find(key); it != v->members.end()) {
+            return it->second;
+        }
+    }
+    return makeNull();
+}
+
 bool
 JSON::forEachDictItem(std::function<void(std::string const& key, JSON value)> fn) const
 {
diff --git a/libtests/json.cc b/libtests/json.cc
index 98e332e7..f265f6f6 100644
--- a/libtests/json.cc
+++ b/libtests/json.cc
@@ -78,6 +78,12 @@ test_main()
     jmap.addDictionaryMember("empty_dict", JSON::makeDictionary());
     jmap.addDictionaryMember("empty_list", JSON::makeArray());
     jmap.addDictionaryMember("single", JSON::makeArray()).addArrayElement(JSON::makeInt(12));
+    std::string jm_str;
+    assert(jmap.getDictItem("b").getString(jm_str));
+    assert(!jmap.getDictItem("b2").getString(jm_str));
+    assert(!jstr2.getDictItem("b").getString(jm_str));
+    assert(jm_str == "a\tb");
+
     check(
         jmap,
         "{\n"