Refactor `QPDF_encryption::decryptStream`: streamline handling of `/Type` and `/…

…DecodeParms` using `Name`, `Dictionary`, and `Array` for improved clarity and consistency, and remove unused test coverage entries.

Refactor `QPDF_encryption::decryptStream`: streamline handling of `/Type` and `/…
…DecodeParms` using `Name`, `Dictionary`, and `Array` for improved clarity and consistency, and remove unused test coverage entries.
m-holger
1 parent c5efd0c3
Showing 2 changed files with 20 additions and 39 deletions
libqpdf/QPDF_encryption.cc
qpdf/qpdf.testcov
@@ -931,12 +931,7 @@ QPDF::decryptStream(
     bool is_root_metadata,
     std::unique_ptr<Pipeline>& decrypt_pipeline)
 {
-    std::string type;
-    if (stream_dict.getKey("/Type").isName()) {
-        type = stream_dict.getKey("/Type").getName();
-    }
-    if (type == "/XRef") {
-        QTC::TC("qpdf", "QPDF_encryption xref stream from encrypted file");
+    if (Name(stream_dict["/Type"]) == "/XRef") {
         return;
     }
     bool use_aes = false;
@@ -945,26 +940,20 @@ QPDF::decryptStream(
         std::string method_source = "/StmF from /Encrypt dictionary";
         if (stream_dict.getKey("/Filter").isOrHasName("/Crypt")) {
-            if (stream_dict.getKey("/DecodeParms").isDictionary()) {
-                QPDFObjectHandle decode_parms = stream_dict.getKey("/DecodeParms");
-                if (decode_parms.isDictionaryOfType("/CryptFilterDecodeParms")) {
-                    QTC::TC("qpdf", "QPDF_encryption stream crypt filter");
-                    method = encp->interpretCF(decode_parms.getKey("/Name"));
+            if (Dictionary decode_parms = stream_dict["/DecodeParms"]) {
+                if (Name(decode_parms["/Type"]) == "/CryptFilterDecodeParms") {
+                    method = encp->interpretCF(decode_parms["/Name"]);
                     method_source = "stream's Crypt decode parameters";
                 }
-            } else if (
-                stream_dict.getKey("/DecodeParms").isArray() &&
-                stream_dict.getKey("/Filter").isArray()) {
-                auto filter = stream_dict.getKey("/Filter");
-                auto decode = stream_dict.getKey("/DecodeParms");
+            } else {
+                Array filter = stream_dict["/Filter"];
+                Array decode = stream_dict.getKey("/DecodeParms");
                 if (filter.size() == decode.size()) {
-                    int i = 0;
-                    for (auto const& item: filter.as_array()) {
-                        if (item.isNameAndEquals("/Crypt")) {
-                            auto crypt_params = decode.getArrayItem(i);
-                            if (crypt_params.isDictionary() &&
-                                crypt_params.getKey("/Name").isName()) {
-                                method = encp->interpretCF(crypt_params.getKey("/Name"));
+                    size_t i = 0;
+                    for (Name item: filter) {
+                        if (item == "/Crypt") {
+                            if (Name name = decode[i]["/Name"]) {
+                                method = encp->interpretCF(name);
                                 method_source = "stream's Crypt decode parameters (array)";
                             }
                             break;
@@ -976,8 +965,7 @@ QPDF::decryptStream(
         }
         if (method == e_unknown) {
-            if ((!encp->encrypt_metadata) && is_root_metadata) {
-                QTC::TC("qpdf", "QPDF_encryption cleartext metadata");
+            if (!encp->encrypt_metadata && is_root_metadata) {
                 method = e_none;
             } else {
                 method = encp->cf_stream;
@@ -1002,13 +990,13 @@ QPDF::decryptStream(
         default:
             // filter local to this stream.
-            qpdf_for_warning.warn(QPDFExc(
-                qpdf_e_damaged_pdf,
-                file->getName(),
-                "",
-                file->getLastOffset(),
-                "unknown encryption filter for streams (check " + method_source +
-                    "); streams may be decrypted improperly"));
+            qpdf_for_warning.warn(
+                {qpdf_e_damaged_pdf,
+                 file->getName(),
+                 "",
+                 file->getLastOffset(),
+                 "unknown encryption filter for streams (check " + method_source +
+                     "); streams may be decrypted improperly"});
             // To avoid repeated warnings, reset cf_stream.  Assume we'd want to use AES if V == 4.
             encp->cf_stream = e_aes;
             use_aes = true;
@@ -1017,11 +1005,9 @@ QPDF::decryptStream(
     }
     std::string key = getKeyForObject(encp, og, use_aes);
     if (use_aes) {
-        QTC::TC("qpdf", "QPDF_encryption aes decode stream");
         decrypt_pipeline =
             std::make_unique<Pl_AES_PDF>("AES stream decryption", pipeline, false, key);
     } else {
-        QTC::TC("qpdf", "QPDF_encryption rc4 decode stream");
         decrypt_pipeline = std::make_unique<Pl_RC4>("RC4 stream decryption", pipeline, key);
     }
     pipeline = decrypt_pipeline.get();
@@ -96,7 +96,6 @@ QPDF recovered stream length 0
 QPDF found wrong endstream in recovery 0
 QPDF_Stream pipeStreamData with null pipeline 0
 QPDFWriter not recompressing /FlateDecode 0
-QPDF_encryption xref stream from encrypted file 0
 QPDFJob unable to filter 0
 QUtil non-trivial UTF-16 0
 QPDF xref overwrite invalid objgen 0
@@ -141,16 +140,12 @@ qpdf-c called qpdf_set_minimum_pdf_version 0
 qpdf-c called qpdf_force_pdf_version 0
 qpdf-c called qpdf_init_write multiple times 0
 QPDF_encryption rc4 decode string 0
-QPDF_encryption rc4 decode stream 0
 QPDFWriter not compressing metadata 0
 QPDF_encryption aes decode string 0
-QPDF_encryption cleartext metadata 0
-QPDF_encryption aes decode stream 0
 QPDFWriter forcing object stream disable 0
 QPDFWriter forced version disabled encryption 0
 qpdf-c called qpdf_set_r4_encryption_parameters_insecure 0
 qpdf-c called qpdf_set_static_aes_IV 0
-QPDF_encryption stream crypt filter 0
 QPDF ERR object stream with wrong type 0
 QPDF object gone after xref reconstruction 0
 qpdf-c called qpdf_has_error 0