Add `validate()` to `NNTree` helpers and implementations

- Introduced a `validate()` method in `QPDFNameTreeObjectHelper`, `QPDFNumberTreeObjectHelper`, and `NNTreeImpl`. - Ensure proper validation of tree keys and values, detecting invalid entries, unsorted keys, and inconsistencies. - Added support for auto-repair in case of validation errors.

Add `validate()` to `NNTree` helpers and implementations
- Introduced a `validate()` method in `QPDFNameTreeObjectHelper`, `QPDFNumberTreeObjectHelper`, and `NNTreeImpl`. - Ensure proper validation of tree keys and values, detecting invalid entries, unsorted keys, and inconsistencies. - Added support for auto-repair in case of validation errors.
m-holger
1 parent 4490c23f
Showing 6 changed files with 58 additions and 2 deletions
include/qpdf/QPDFNameTreeObjectHelper.hh
include/qpdf/QPDFNumberTreeObjectHelper.hh
libqpdf/NNTree.cc
libqpdf/QPDFNameTreeObjectHelper.cc
libqpdf/QPDFNumberTreeObjectHelper.cc
libqpdf/qpdf/NNTree.hh
@@ -50,7 +50,13 @@ class QPDF_DLL_CLASS QPDFNameTreeObjectHelper: public QPDFObjectHelper
         QPDFObjectHandle,
         QPDF&,
         std::function<bool(QPDFObjectHandle const&)> value_validator,
-        bool auto_repair = true);
+        bool auto_repair);
+
+    // Validate the name tree. Returns true if the tree is valid.
+    //
+    // If the tree is not valid and auto_repair is true, attempt to repair the tree.
+    QPDF_DLL
+    bool validate(bool repair = true);
     // Create an empty name tree
     QPDF_DLL
@@ -48,7 +48,7 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
         QPDFObjectHandle,
         QPDF&,
         std::function<bool(QPDFObjectHandle const&)> value_validator,
-        bool auto_repair = true);
+        bool auto_repair);
     QPDF_DLL
     ~QPDFNumberTreeObjectHelper() override;
@@ -59,6 +59,12 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
     typedef long long int numtree_number;
+    // Validate the name tree. Returns true if the tree is valid.
+    //
+    // If the tree is not valid and auto_repair is true, attempt to repair the tree.
+    QPDF_DLL
+    bool validate(bool repair = true);
+
     // Return overall minimum and maximum indices
     QPDF_DLL
     numtree_number getMin();
@@ -891,3 +891,33 @@ NNTreeImpl::remove(QPDFObjectHandle const&amp; key, QPDFObjectHandle* value)
     iter.remove();
     return true;
 }
+
+bool
+NNTreeImpl::validate(bool a_repair)
+{
+    bool first = true;
+    QPDFObjectHandle last_key;
+    try {
+        for (auto const& [key, value]: *this) {
+            if (!details.keyValid(key)) {
+                error(oh, "invalid key in validate");
+            }
+            if (!value_valid(value)) {
+                error(oh, "invalid value in validate");
+            }
+            if (first) {
+                first = false;
+            } else if (last_key && details.compareKeys(last_key, key) != -1) {
+                error(oh, "keys are not sorted in validate");
+            }
+            last_key = key;
+        }
+    } catch (QPDFExc& e) {
+        if (a_repair) {
+            warn(oh, std::string("attempting to repair after error: ") + e.what());
+            repair();
+        }
+        return false;
+    }
+    return true;
+}
@@ -215,3 +215,9 @@ QPDFNameTreeObjectHelper::getAsMap() const
     result.insert(begin(), end());
     return result;
 }
+
+bool
+QPDFNameTreeObjectHelper::validate(bool repair)
+{
+    return m->impl->validate(repair);
+}
@@ -251,3 +251,9 @@ QPDFNumberTreeObjectHelper::getAsMap() const
     result.insert(begin(), end());
     return result;
 }
+
+bool
+QPDFNumberTreeObjectHelper::validate(bool repair)
+{
+    return m->impl->validate(repair);
+}
@@ -109,6 +109,8 @@ class NNTreeImpl
     iterator insert(QPDFObjectHandle const& key, QPDFObjectHandle const& value);
     bool remove(QPDFObjectHandle const& key, QPDFObjectHandle* value = nullptr);
+    bool validate(bool repair = true);
+
     // Change the split threshold for easier testing. There's no real reason to expose this to
     // downstream tree helpers, but it has to be public so we can call it from the test suite.
     void setSplitThreshold(int split_threshold);