Merge pull request #730 from m-holger/allpages

Tidy QPDF::getAllPagesInternal and QPDF::pushInheritedAttributesToPageInternal

Merge pull request #730 from m-holger/allpages
Tidy QPDF::getAllPagesInternal and QPDF::pushInheritedAttributesToPageInternal
Jay Berkenbilt · GitHub
2 parents f8fd7d60 903a8664
Showing 5 changed files with 123 additions and 173 deletions
include/qpdf/QPDF.hh
libqpdf/QPDF_optimization.cc
libqpdf/QPDF_pages.cc
qpdf/qtest/qpdf/no-pages-types-fix.out
qpdf/qtest/qpdf/no-pages-types.out
@@ -1240,7 +1240,6 @@ class QPDF
     void getAllPagesInternal(
         QPDFObjectHandle cur_pages,
-        std::vector<QPDFObjectHandle>& result,
         std::set<QPDFObjGen>& visited,
         std::set<QPDFObjGen>& seen);
     void insertPage(QPDFObjectHandle newpage, int pos);
@@ -1627,10 +1626,8 @@ class QPDF
     void pushInheritedAttributesToPageInternal(
         QPDFObjectHandle,
         std::map<std::string, std::vector<QPDFObjectHandle>>&,
-        std::vector<QPDFObjectHandle>& all_pages,
         bool allow_changes,
-        bool warn_skipped_keys,
-        std::set<QPDFObjGen>& visited);
+        bool warn_skipped_keys);
     void updateObjectMaps(
         ObjUser const& ou,
         QPDFObjectHandle oh,
@@ -148,15 +148,11 @@ QPDF::pushInheritedAttributesToPage(bool allow_changes, bool warn_skipped_keys)
     // key_ancestors is a mapping of page attribute keys to a stack of
     // Pages nodes that contain values for them.
     std::map<std::string, std::vector<QPDFObjectHandle>> key_ancestors;
-    this->m->all_pages.clear();
-    std::set<QPDFObjGen> visited;
     pushInheritedAttributesToPageInternal(
         this->m->trailer.getKey("/Root").getKey("/Pages"),
         key_ancestors,
-        this->m->all_pages,
         allow_changes,
-        warn_skipped_keys,
-        visited);
+        warn_skipped_keys);
     if (!key_ancestors.empty()) {
         throw std::logic_error("key_ancestors not empty after"
                                " pushing inherited attributes to pages");
@@ -169,154 +165,112 @@ void
 QPDF::pushInheritedAttributesToPageInternal(
     QPDFObjectHandle cur_pages,
     std::map<std::string, std::vector<QPDFObjectHandle>>& key_ancestors,
-    std::vector<QPDFObjectHandle>& pages,
     bool allow_changes,
-    bool warn_skipped_keys,
-    std::set<QPDFObjGen>& visited)
+    bool warn_skipped_keys)
 {
-    QPDFObjGen this_og = cur_pages.getObjGen();
-    if (visited.count(this_og) > 0) {
-        throw QPDFExc(
-            qpdf_e_pages,
-            this->m->file->getName(),
-            this->m->last_object_description,
-            0,
-            "Loop detected in /Pages structure (inherited attributes)");
-    }
-    visited.insert(this_og);
-
-    if (!cur_pages.isDictionary()) {
-        throw QPDFExc(
-            qpdf_e_damaged_pdf,
-            this->m->file->getName(),
-            this->m->last_object_description,
-            this->m->file->getLastOffset(),
-            "invalid object in page tree");
-    }
-
-    // Extract the underlying dictionary object
-    std::string type = cur_pages.getKey("/Type").getName();
-
-    if (type == "/Pages") {
-        // Make a list of inheritable keys. Only the keys /MediaBox,
-        // /CropBox, /Resources, and /Rotate are inheritable
-        // attributes. Push this object onto the stack of pages nodes
-        // that have values for this attribute.
-
-        std::set<std::string> inheritable_keys;
-        for (auto const& key: cur_pages.getKeys()) {
-            if ((key == "/MediaBox") || (key == "/CropBox") ||
-                (key == "/Resources") || (key == "/Rotate")) {
-                if (!allow_changes) {
-                    throw QPDFExc(
-                        qpdf_e_internal,
-                        this->m->file->getName(),
-                        this->m->last_object_description,
-                        this->m->file->getLastOffset(),
-                        "optimize detected an "
-                        "inheritable attribute when called "
-                        "in no-change mode");
-                }
+    // Make a list of inheritable keys. Only the keys /MediaBox,
+    // /CropBox, /Resources, and /Rotate are inheritable
+    // attributes. Push this object onto the stack of pages nodes
+    // that have values for this attribute.
+
+    std::set<std::string> inheritable_keys;
+    for (auto const& key: cur_pages.getKeys()) {
+        if ((key == "/MediaBox") || (key == "/CropBox") ||
+            (key == "/Resources") || (key == "/Rotate")) {
+            if (!allow_changes) {
+                throw QPDFExc(
+                    qpdf_e_internal,
+                    this->m->file->getName(),
+                    this->m->last_object_description,
+                    this->m->file->getLastOffset(),
+                    "optimize detected an "
+                    "inheritable attribute when called "
+                    "in no-change mode");
+            }
-                // This is an inheritable resource
-                inheritable_keys.insert(key);
-                QPDFObjectHandle oh = cur_pages.getKey(key);
-                QTC::TC(
-                    "qpdf",
-                    "QPDF opt direct pages resource",
-                    oh.isIndirect() ? 0 : 1);
-                if (!oh.isIndirect()) {
-                    if (!oh.isScalar()) {
-                        // Replace shared direct object non-scalar
-                        // resources with indirect objects to avoid
-                        // copying large structures around.
-                        cur_pages.replaceKey(key, makeIndirectObject(oh));
-                        oh = cur_pages.getKey(key);
-                    } else {
-                        // It's okay to copy scalars.
-                        QTC::TC("qpdf", "QPDF opt inherited scalar");
-                    }
-                }
-                key_ancestors[key].push_back(oh);
-                if (key_ancestors[key].size() > 1) {
-                    QTC::TC("qpdf", "QPDF opt key ancestors depth > 1");
-                }
-                // Remove this resource from this node.  It will be
-                // reattached at the page level.
-                cur_pages.removeKey(key);
-            } else if (!((key == "/Type") || (key == "/Parent") ||
-                         (key == "/Kids") || (key == "/Count"))) {
-                // Warn when flattening, but not if the key is at the top
-                // level (i.e. "/Parent" not set), as we don't change these;
-                // but flattening removes intermediate /Pages nodes.
-                if ((warn_skipped_keys) && (cur_pages.hasKey("/Parent"))) {
-                    QTC::TC("qpdf", "QPDF unknown key not inherited");
-                    setLastObjectDescription(
-                        "Pages object", cur_pages.getObjGen());
-                    warn(
-                        qpdf_e_pages,
-                        this->m->last_object_description,
-                        0,
-                        ("Unknown key " + key +
-                         " in /Pages object"
-                         " is being discarded as a result of"
-                         " flattening the /Pages tree"));
+            // This is an inheritable resource
+            inheritable_keys.insert(key);
+            QPDFObjectHandle oh = cur_pages.getKey(key);
+            QTC::TC(
+                "qpdf",
+                "QPDF opt direct pages resource",
+                oh.isIndirect() ? 0 : 1);
+            if (!oh.isIndirect()) {
+                if (!oh.isScalar()) {
+                    // Replace shared direct object non-scalar
+                    // resources with indirect objects to avoid
+                    // copying large structures around.
+                    cur_pages.replaceKey(key, makeIndirectObject(oh));
+                    oh = cur_pages.getKey(key);
+                } else {
+                    // It's okay to copy scalars.
+                    QTC::TC("qpdf", "QPDF opt inherited scalar");
                 }
             }
+            key_ancestors[key].push_back(oh);
+            if (key_ancestors[key].size() > 1) {
+                QTC::TC("qpdf", "QPDF opt key ancestors depth > 1");
+            }
+            // Remove this resource from this node.  It will be
+            // reattached at the page level.
+            cur_pages.removeKey(key);
+        } else if (!((key == "/Type") || (key == "/Parent") ||
+                     (key == "/Kids") || (key == "/Count"))) {
+            // Warn when flattening, but not if the key is at the top
+            // level (i.e. "/Parent" not set), as we don't change these;
+            // but flattening removes intermediate /Pages nodes.
+            if ((warn_skipped_keys) && (cur_pages.hasKey("/Parent"))) {
+                QTC::TC("qpdf", "QPDF unknown key not inherited");
+                setLastObjectDescription("Pages object", cur_pages.getObjGen());
+                warn(
+                    qpdf_e_pages,
+                    this->m->last_object_description,
+                    0,
+                    ("Unknown key " + key +
+                     " in /Pages object"
+                     " is being discarded as a result of"
+                     " flattening the /Pages tree"));
+            }
         }
+    }
-        // Visit descendant nodes.
-        QPDFObjectHandle kids = cur_pages.getKey("/Kids");
-        int n = kids.getArrayNItems();
-        for (int i = 0; i < n; ++i) {
+    // Process descendant nodes.
+    for (auto& kid: cur_pages.getKey("/Kids").aitems()) {
+        if (kid.isDictionaryOfType("/Pages")) {
             pushInheritedAttributesToPageInternal(
-                kids.getArrayItem(i),
-                key_ancestors,
-                pages,
-                allow_changes,
-                warn_skipped_keys,
-                visited);
-        }
-
-        // For each inheritable key, pop the stack.  If the stack
-        // becomes empty, remove it from the map.  That way, the
-        // invariant that the list of keys in key_ancestors is exactly
-        // those keys for which inheritable attributes are available.
-
-        if (!inheritable_keys.empty()) {
-            QTC::TC("qpdf", "QPDF opt inheritable keys");
-            for (auto const& key: inheritable_keys) {
-                key_ancestors[key].pop_back();
-                if (key_ancestors[key].empty()) {
-                    QTC::TC("qpdf", "QPDF opt erase empty key ancestor");
-                    key_ancestors.erase(key);
+                kid, key_ancestors, allow_changes, warn_skipped_keys);
+        } else {
+            // Add all available inheritable attributes not present in
+            // this object to this object.
+            for (auto const& iter: key_ancestors) {
+                std::string const& key = iter.first;
+                if (!kid.hasKey(key)) {
+                    QTC::TC("qpdf", "QPDF opt resource inherited");
+                    kid.replaceKey(key, iter.second.back());
+                } else {
+                    QTC::TC("qpdf", "QPDF opt page resource hides ancestor");
                 }
             }
-        } else {
-            QTC::TC("qpdf", "QPDF opt no inheritable keys");
         }
-    } else if (type == "/Page") {
-        // Add all available inheritable attributes not present in
-        // this object to this object.
-        for (auto const& iter: key_ancestors) {
-            std::string const& key = iter.first;
-            if (!cur_pages.hasKey(key)) {
-                QTC::TC("qpdf", "QPDF opt resource inherited");
-                cur_pages.replaceKey(key, iter.second.back());
-            } else {
-                QTC::TC("qpdf", "QPDF opt page resource hides ancestor");
+    }
+
+    // For each inheritable key, pop the stack.  If the stack
+    // becomes empty, remove it from the map.  That way, the
+    // invariant that the list of keys in key_ancestors is exactly
+    // those keys for which inheritable attributes are available.
+
+    if (!inheritable_keys.empty()) {
+        QTC::TC("qpdf", "QPDF opt inheritable keys");
+        for (auto const& key: inheritable_keys) {
+            key_ancestors[key].pop_back();
+            if (key_ancestors[key].empty()) {
+                QTC::TC("qpdf", "QPDF opt erase empty key ancestor");
+                key_ancestors.erase(key);
             }
         }
-        pages.push_back(cur_pages);
     } else {
-        throw QPDFExc(
-            qpdf_e_damaged_pdf,
-            this->m->file->getName(),
-            this->m->last_object_description,
-            this->m->file->getLastOffset(),
-            "invalid Type " + type + " in page tree");
+        QTC::TC("qpdf", "QPDF opt no inheritable keys");
     }
-    visited.erase(this_og);
 }
 void
@@ -82,7 +82,10 @@ QPDF::getAllPages()
             getRoot().replaceKey("/Pages", pages);
         }
         seen.clear();
-        getAllPagesInternal(pages, this->m->all_pages, visited, seen);
+        if (pages.hasKey("/Kids")) {
+            // Ensure we actually found a /Pages object.
+            getAllPagesInternal(pages, visited, seen);
+        }
     }
     return this->m->all_pages;
 }
@@ -90,12 +93,11 @@ QPDF::getAllPages()
 void
 QPDF::getAllPagesInternal(
     QPDFObjectHandle cur_node,
-    std::vector<QPDFObjectHandle>& result,
     std::set<QPDFObjGen>& visited,
     std::set<QPDFObjGen>& seen)
 {
-    QPDFObjGen this_og = cur_node.getObjGen();
-    if (visited.count(this_og) > 0) {
+    QPDFObjGen cur_node_og = cur_node.getObjGen();
+    if (visited.count(cur_node_og) > 0) {
         throw QPDFExc(
             qpdf_e_pages,
             this->m->file->getName(),
@@ -103,14 +105,19 @@ QPDF::getAllPagesInternal(
             0,
             "Loop detected in /Pages structure (getAllPages)");
     }
-    visited.insert(this_og);
-    std::string wanted_type;
-    if (cur_node.hasKey("/Kids")) {
-        wanted_type = "/Pages";
-        QPDFObjectHandle kids = cur_node.getKey("/Kids");
-        int n = kids.getArrayNItems();
-        for (int i = 0; i < n; ++i) {
-            QPDFObjectHandle kid = kids.getArrayItem(i);
+    visited.insert(cur_node_og);
+    if (!cur_node.isDictionaryOfType("/Pages")) {
+        cur_node.warnIfPossible(
+            "/Type key should be /Pages but is not; overriding");
+        cur_node.replaceKey("/Type", "/Pages"_qpdf);
+    }
+    auto kids = cur_node.getKey("/Kids");
+    int n = kids.getArrayNItems();
+    for (int i = 0; i < n; ++i) {
+        auto kid = kids.getArrayItem(i);
+        if (kid.hasKey("/Kids")) {
+            getAllPagesInternal(kid, visited, seen);
+        } else {
             if (!kid.isIndirect()) {
                 QTC::TC("qpdf", "QPDF handle direct page object");
                 cur_node.warnIfPossible(
@@ -129,23 +136,15 @@ QPDF::getAllPagesInternal(
                 kid = makeIndirectObject(QPDFObjectHandle(kid).shallowCopy());
                 kids.setArrayItem(i, kid);
             }
-            getAllPagesInternal(kid, result, visited, seen);
+            if (!kid.isDictionaryOfType("/Page")) {
+                kid.warnIfPossible(
+                    "/Type key should be /Page but is not; overriding");
+                kid.replaceKey("/Type", "/Page"_qpdf);
+            }
+            seen.insert(kid.getObjGen());
+            m->all_pages.push_back(kid);
         }
-    } else {
-        wanted_type = "/Page";
-        seen.insert(this_og);
-        result.push_back(cur_node);
-    }
-
-    if (!cur_node.isDictionaryOfType(wanted_type)) {
-        warn(
-            qpdf_e_damaged_pdf,
-            "page tree node",
-            this->m->file->getLastOffset(),
-            "/Type key should be " + wanted_type + " but is not; overriding");
-        cur_node.replaceKey("/Type", QPDFObjectHandle::newName(wanted_type));
     }
-    visited.erase(this_og);
 }
 void
-WARNING: no-pages-types.pdf (page tree node, offset 307): /Type key should be /Page but is not; overriding
-WARNING: no-pages-types.pdf (page tree node, offset 307): /Type key should be /Pages but is not; overriding
+WARNING: no-pages-types.pdf, object 2 0 at offset 73: /Type key should be /Pages but is not; overriding
+WARNING: no-pages-types.pdf, object 3 0 at offset 145: /Type key should be /Page but is not; overriding
 qpdf: operation succeeded with warnings; resulting file may have some problems
@@ -2,6 +2,6 @@ checking no-pages-types.pdf
 PDF Version: 1.3
 File is not encrypted
 File is not linearized
-WARNING: no-pages-types.pdf (page tree node, offset 307): /Type key should be /Page but is not; overriding
-WARNING: no-pages-types.pdf (page tree node, offset 307): /Type key should be /Pages but is not; overriding
+WARNING: no-pages-types.pdf, object 2 0 at offset 73: /Type key should be /Pages but is not; overriding
+WARNING: no-pages-types.pdf, object 3 0 at offset 145: /Type key should be /Page but is not; overriding
 qpdf: operation succeeded with warnings