Implement JSON v2 for Stream

Not fully exercised in this commit

Implement JSON v2 for Stream
Not fully exercised in this commit
Jay Berkenbilt
1 parent 3246923c
Showing 10 changed files with 199 additions and 13 deletions
TODO
include/qpdf/Constants.h
include/qpdf/QPDFObjectHandle.hh
libqpdf/QPDFObjectHandle.cc
libqpdf/QPDF_Stream.cc
libqpdf/qpdf/QPDF_Stream.hh
qpdf/qtest/qpdf/direct-pages-json-objects.out
qpdf/qtest/qpdf/direct-pages-json-pages.out
qpdf/qtest/qpdf/page_api_2-json-objects.out
qpdf/qtest/qpdf/page_api_2-json-pages.out
@@ -63,6 +63,8 @@ General things to remember:
  
 * Remember typo: search for "Typo" In QPDFJob::doJSONEncrypt.
  
+* Test stream with invalid data
+
 * Consider using camelCase in multi-word key names to be consistent
   with job JSON and with how JSON is often represented in languages
   that use it more natively.
@@ -99,6 +99,12 @@ enum qpdf_stream_decode_level_e {
     qpdf_dl_specialized, /* also decode other non-lossy filters */
     qpdf_dl_all          /* also decode lossy filters */
 };
+/* For JSON encoding */
+enum qpdf_stream_data_json_e {
+    qpdf_sj_none = 0,
+    qpdf_sj_inline,
+    qpdf_sj_file,
+};
  
 /* R3 Encryption Parameters */
  
@@ -1339,8 +1339,8 @@ class QPDFObjectHandle
     //     unambiguous. The getStreamJSON() call can be used to add
     //     encoding of the stream's data.
     // * Object types that are only valid in content streams (inline
-    //   image, operator) as well as "reserved" objects are not
-    //   representable and will be serialized as "null".
+    //   image, operator) are serialized as "null". Attempting to
+    //   serialize a "reserved" object is an error.
     // If dereference_indirect is true and this is an indirect object,
     // show the actual contents of the object. The effect of
     // dereference_indirect applies only to this object. It is not
@@ -1350,9 +1350,42 @@ class QPDFObjectHandle
  
     // Deprecated version uses v1 for backward compatibility.
     // ABI: remove for qpdf 12
-    [[deprecated("Use getJSON(int version)")]]
-    QPDF_DLL
-    JSON getJSON(bool dereference_indirect = false);
+    [[deprecated("Use getJSON(int version)")]] QPDF_DLL JSON
+    getJSON(bool dereference_indirect = false);
+
+    // This method can be called on a stream to get a more extended
+    // JSON representation of the stream that includes the stream's
+    // data. The JSON object returned is always a dictionary whose
+    // "dict" key is an encoding of the stream's dictionary. The
+    // representation of the data is determined by the json_data
+    // field.
+    //
+    // The json_data field may have the value qpdf_sj_none,
+    // qpdf_sj_inline, or qpdf_sj_file.
+    //
+    // If json_data is qpdf_sj_none, stream data is not represented.
+    //
+    // If json_data is qpdf_sj_inline or qpdf_sj_file, then stream
+    // data is filtered or not based on the value of decode_level,
+    // which has the same meaning as with pipeStreamData.
+    //
+    // If json_data is qpdf_sj_inline, the base64-encoded stream data
+    // is included in the "data" field of the dictionary that is
+    // returned.
+    //
+    // If json_data is qpdf_sj_file, then the Pipeline ("p") and
+    // data_filename argument must be supplied. The value of
+    // data_filename is stored in the resulting json in the "datafile"
+    // key but is not otherwise use. The stream data itself (raw or
+    // filtered depending on decode level), is written to the
+    // pipeline via pipeStreamData().
+    QPDF_DLL
+    JSON getStreamJSON(
+        int json_version,
+        qpdf_stream_data_json_e json_data,
+        qpdf_stream_decode_level_e decode_level,
+        Pipeline* p,
+        std::string const& data_filename);
  
     // Legacy helper methods for commonly performed operations on
     // pages. Newer code should use QPDFPageObjectHelper instead. The
@@ -1797,6 +1797,19 @@ QPDFObjectHandle::getJSON(int json_version, bool dereference_indirect)
     }
 }
  
+JSON
+QPDFObjectHandle::getStreamJSON(
+    int json_version,
+    qpdf_stream_data_json_e json_data,
+    qpdf_stream_decode_level_e decode_level,
+    Pipeline* p,
+    std::string const& data_filename)
+{
+    assertStream();
+    return dynamic_cast<QPDF_Stream*>(obj.get())->getStreamJSON(
+        json_version, json_data, decode_level, p, data_filename);
+}
+
 QPDFObjectHandle
 QPDFObjectHandle::wrapInArray()
 {
@@ -2,8 +2,10 @@
  
 #include <qpdf/ContentNormalizer.hh>
 #include <qpdf/Pipeline.hh>
+#include <qpdf/Pl_Base64.hh>
 #include <qpdf/Pl_Buffer.hh>
 #include <qpdf/Pl_Count.hh>
+#include <qpdf/Pl_Discard.hh>
 #include <qpdf/Pl_Flate.hh>
 #include <qpdf/Pl_QPDFTokenizer.hh>
 #include <qpdf/QIntC.hh>
@@ -54,6 +56,18 @@ namespace
             return nullptr;
         }
     };
+
+    class StreamBlobProvider
+    {
+      public:
+        StreamBlobProvider(
+            QPDF_Stream* stream, qpdf_stream_decode_level_e decode_level);
+        void operator()(Pipeline*);
+
+      private:
+        QPDF_Stream* stream;
+        qpdf_stream_decode_level_e decode_level;
+    };
 } // namespace
  
 std::map<std::string, std::string> QPDF_Stream::filter_abbreviations = {
@@ -81,6 +95,19 @@ std::map&lt;std::string, std::function&lt;std::shared_ptr&lt;QPDFStreamFilter&gt;()&gt;&gt;
         {"/ASCIIHexDecode", SF_ASCIIHexDecode::factory},
 };
  
+StreamBlobProvider::StreamBlobProvider(
+    QPDF_Stream* stream, qpdf_stream_decode_level_e decode_level) :
+    stream(stream),
+    decode_level(decode_level)
+{
+}
+
+void
+StreamBlobProvider::operator()(Pipeline* p)
+{
+    this->stream->pipeStreamData(p, nullptr, 0, decode_level, false, false);
+}
+
 QPDF_Stream::QPDF_Stream(
     QPDF* qpdf,
     int objid,
@@ -153,8 +180,95 @@ QPDF_Stream::unparse()
 JSON
 QPDF_Stream::getJSON(int json_version)
 {
-    // QXXXQ
-    return this->stream_dict.getJSON(json_version);
+    if (json_version == 1) {
+        return this->stream_dict.getJSON(json_version);
+    }
+    return getStreamJSON(json_version, qpdf_sj_none, qpdf_dl_none, nullptr, "");
+}
+
+JSON
+QPDF_Stream::getStreamJSON(
+    int json_version,
+    qpdf_stream_data_json_e json_data,
+    qpdf_stream_decode_level_e decode_level,
+    Pipeline* p,
+    std::string const& data_filename)
+{
+    switch (json_data) {
+    case qpdf_sj_none:
+    case qpdf_sj_inline:
+        if (p != nullptr) {
+            throw std::logic_error("QPDF_Stream::getStreamJSON: pipline should "
+                                   "only be suppiled json_data is file");
+        }
+        break;
+    case qpdf_sj_file:
+        if (p == nullptr) {
+            throw std::logic_error("QPDF_Stream::getStreamJSON: pipline must "
+                                   "be be suppiled json_data is file");
+        }
+        if (data_filename.empty()) {
+            throw std::logic_error("QPDF_Stream::getStreamJSON: data_filename "
+                                   "must be supplied when json_data is file");
+        }
+        break;
+    }
+
+    auto dict = this->stream_dict;
+    JSON result = JSON::makeDictionary();
+    if (json_data != qpdf_sj_none) {
+        std::shared_ptr<Buffer> buf;
+        bool filtered = false;
+        bool filter = (decode_level != qpdf_dl_none);
+        for (int attempt = 1; attempt <= 2; ++attempt) {
+            Pl_Discard discard;
+            std::shared_ptr<Pl_Buffer> buf_pl;
+            Pipeline* data_pipeline = nullptr;
+            if (json_data == qpdf_sj_file) {
+                // We need to capture the data to write
+                buf_pl = std::make_shared<Pl_Buffer>("stream data");
+                data_pipeline = buf_pl.get();
+            } else {
+                data_pipeline = &discard;
+            }
+            filtered = pipeStreamData(
+                data_pipeline, nullptr, 0, decode_level, false, (attempt == 1));
+            if (filter && (!filtered)) {
+                // Try again
+                filter = false;
+            } else {
+                if (buf_pl.get()) {
+                    buf = buf_pl->getBufferSharedPointer();
+                }
+                break;
+            }
+        }
+        // We can use unsafeShallowCopy because we are only
+        // touching top-level keys.
+        dict = this->stream_dict.unsafeShallowCopy();
+        dict.removeKey("/Length");
+        if (filtered) {
+            dict.removeKey("/Filter");
+            dict.removeKey("/DecodeParms");
+        }
+        if (json_data == qpdf_sj_file) {
+            result.addDictionaryMember(
+                "datafile", JSON::makeString(data_filename));
+            if (!buf.get()) {
+                throw std::logic_error(
+                    "QPDF_Stream: failed to get stream data in json file mode");
+            }
+            p->write(buf->getBuffer(), buf->getSize());
+        } else if (json_data == qpdf_sj_inline) {
+            result.addDictionaryMember(
+                "data", JSON::makeBlob(StreamBlobProvider(this, decode_level)));
+        } else {
+            throw std::logic_error(
+                "QPDF_Stream: unexpected value of json_data");
+        }
+    }
+    result.addDictionaryMember("dict", dict.getJSON(json_version));
+    return result;
 }
  
 QPDFObject::object_type_e
@@ -61,6 +61,12 @@ class QPDF_Stream: public QPDFObject
         QPDFObjectHandle const& decode_parms);
     void
     addTokenFilter(std::shared_ptr<QPDFObjectHandle::TokenFilter> token_filter);
+    JSON getStreamJSON(
+        int json_version,
+        qpdf_stream_data_json_e json_data,
+        qpdf_stream_decode_level_e decode_level,
+        Pipeline* p,
+        std::string const& data_filename);
  
     void replaceDict(QPDFObjectHandle const& new_dict);
  
@@ -49,7 +49,9 @@
       "/Type": "/Pages"
     },
     "3 0 R": {
-      "/Length": "4 0 R"
+      "dict": {
+        "/Length": "4 0 R"
+      }
     },
     "4 0 R": 44,
     "5 0 R": {
@@ -39,7 +39,9 @@
       "/Type": "/Pages"
     },
     "3 0 R": {
-      "/Length": "4 0 R"
+      "dict": {
+        "/Length": "4 0 R"
+      }
     },
     "4 0 R": 44,
     "5 0 R": {
@@ -62,7 +62,9 @@
       "/Type": "/Page"
     },
     "6 0 R": {
-      "/Length": "7 0 R"
+      "dict": {
+        "/Length": "7 0 R"
+      }
     },
     "7 0 R": 47,
     "8 0 R": {
@@ -72,7 +74,9 @@
       "/Type": "/Font"
     },
     "9 0 R": {
-      "/Length": "10 0 R"
+      "dict": {
+        "/Length": "10 0 R"
+      }
     },
     "10 0 R": 47,
     "trailer": {
@@ -94,7 +94,9 @@
       "/Type": "/Page"
     },
     "6 0 R": {
-      "/Length": "7 0 R"
+      "dict": {
+        "/Length": "7 0 R"
+      }
     },
     "7 0 R": 47,
     "8 0 R": {
@@ -104,7 +106,9 @@
       "/Type": "/Font"
     },
     "9 0 R": {
-      "/Length": "10 0 R"
+      "dict": {
+        "/Length": "10 0 R"
+      }
     },
     "10 0 R": 47,
     "11 0 R": {