Explicitly test ignoring unknown keys in JSON input

Jay Berkenbilt
1 parent dc8df962
Showing 4 changed files with 38 additions and 16 deletions
TODO
libqpdf/QPDF_json.cc
qpdf/qpdf.testcov
qpdf/qtest/qpdf/manual-qpdf-json.json
@@ -97,6 +97,9 @@ General things to remember:
  
 * Add json to the large file tests.
  
+* Document that keys other than "qpdf-v2" are ignored so people can
+  stash their own stuff.
+
 JSON to PDF:
  
 Have --json-input and --update-from-json. With --json-input, the json
@@ -170,7 +170,7 @@ QPDF::JSONReactor::containerEnd(JSON const&amp; value)
         }
     } else if (state == st_objects) {
         if (parse_error) {
-            // ignore
+            QTC::TC("qpdf", "QPDF_json don't check object after parse error");
         } else if (cur_object == "trailer") {
             if (!saw_value) {
                 QTC::TC("qpdf", "QPDF_json trailer no value");
@@ -279,9 +279,9 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             this->saw_qpdf = true;
             nestedState(key, value, st_qpdf);
         } else {
-            // Ignore all other fields for forward compatibility.
-            // Don't use nestedState since this can be any type.
-            // QXXXQ QTC
+            // Ignore all other fields. We explicitly allow people to
+            // add other top-level keys for their own use.
+            QTC::TC("qpdf", "QPDF_json ignoring unknown top-level key");
             next_state = st_ignore;
         }
     } else if (state == st_qpdf) {
@@ -304,8 +304,9 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             this->saw_objects = true;
             nestedState(key, value, st_objects);
         } else {
-            // ignore unknown keys for forward compatibility
-            // QXXXQ QTC
+            // ignore unknown keys for forward compatibility and to
+            // skip keys we don't care about like "maxobjectid".
+            QTC::TC("qpdf", "QPDF_json ignore second-level key");
             next_state = st_ignore;
         }
     } else if (state == st_objects) {
@@ -351,7 +352,7 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             }
         } else {
             // Ignore unknown keys for forward compatibility
-            // QXXXQ QTC
+            QTC::TC("qpdf", "QPDF_json ignore unknown key in object_top");
             next_state = st_ignore;
         }
         if (replacement.isInitialized()) {
@@ -373,7 +374,7 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             parse_error = true;
         } else {
             // Ignore unknown keys for forward compatibility
-            // QXXXQ QTC
+            QTC::TC("qpdf", "QPDF_json ignore unknown key in trailer");
             next_state = st_ignore;
         }
     } else if (state == st_stream) {
@@ -430,7 +431,7 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             }
         } else {
             // Ignore unknown keys for forward compatibility.
-            // QXXXQ QTC
+            QTC::TC("qpdf", "QPDF_json ignore unknown key in stream");
             next_state = st_ignore;
         }
     } else if (state == st_object) {
@@ -549,12 +550,6 @@ QPDF::importJSON(std::shared_ptr&lt;InputSource&gt; is, bool must_be_complete)
     if (reactor.anyErrors()) {
         throw std::runtime_error(is->getName() + ": errors found in JSON");
     }
-    // QXXXQ
-    // std::cout << "trailer:\n" << getTrailer().unparse() << std::endl;
-    // for (auto& oh: getAllObjects()) {
-    //     std::cout << oh.unparse() << ":" << std::endl;
-    //     std::cout << oh.unparseResolved() << std::endl;
-    // }
 }
  
 void
@@ -669,3 +669,9 @@ QPDF_json value stream both or neither 0
 QPDFJob need json-stream-prefix for stdout 0
 QPDFJob write json to stdout 0
 QPDFJob write json to file 0
+QPDF_json don't check object after parse error 0
+QPDF_json ignoring unknown top-level key 0
+QPDF_json ignore second-level key 0
+QPDF_json ignore unknown key in object_top 0
+QPDF_json ignore unknown key in trailer 0
+QPDF_json ignore unknown key in stream 0
 {
+  "comment": [
+    "We allow and ignore other top-level keys"
+  ],
   "qpdf-v2": {
     "pdfversion": "2.0",
+    "maybe-future-key": {
+      "x": [
+        "Lots of times we ignore things",
+        "for forward-compatibility so we don't have",
+        "to change the version number if we add stuff",
+        "in the future"
+      ]
+    },
     "objects": {
       "obj:3 0 R": {
         "value": {
@@ -19,7 +30,8 @@
             "/ProcSet": "5 0 R"
           },
           "/Type": "/Page"
-        }
+        },
+        "ignore": "this is ignored"
       },
       "obj:2 0 R": {
         "value": {
@@ -28,6 +40,10 @@
             "3 0 R"
           ],
           "/Type": "/Pages"
+        },
+        "ignore": {
+          "potato": "salad",
+          "this": ["is ignored too"]
         }
       },
       "obj:1 0 R": {
@@ -38,6 +54,7 @@
       },
       "obj:4 0 R": {
         "stream": {
+          "what-is-this": "doesn't matter",
           "dict": {},
           "data": "QlQKICAvRjEgMjQgVGYKICA3MiA3MjAgVGQKICAoUG90YXRvKSBUagpFVAo="
         }
@@ -58,6 +75,7 @@
         }
       },
       "trailer": {
+        "even-here-we-ignore": "stuff",
         "value": {
           "/QTest": "7 0 R",
           "/Root": "1 0 R",