Use QPDF_DLL_CLASS with Pipeline and InputSource subclasses

This enables RTTI so we can use dynamic_cast on them across the shared
object boundary.

README-maintainer

@@ -156,9 +156,14 @@ CODING RULES
 
 * Use QPDF_DLL on all methods that are to be exported in the shared
   library/DLL. Use QPDF_DLL_CLASS for all classes whose type
-  information is needed. This is important for exception classes and
+  information is needed. This is important for classes that are used
-  it seems also for classes that are intended to be subclassed across
+  as exceptions, subclassed, or tested with dynamic_cast across the
-  the shared library boundary.
+  the shared object boundary (or "shared library boundary" -- we may
+  use either term in comments and documentation). In particular,
+  anything new derived from Pipeline or InputSource should be marked
+  with QPDF_DLL_CLASS, but we don't need to do it for QPDFObjectHelper
+  or QPDFDocumentHelper subclasses since there's no reason to use
+  dynamic_cast with those.
 
 * Put private member variables in std::shared_ptr<Members> for all
   public classes. Remember to use QPDF_DLL on ~Members(). Exception:

include/qpdf/BufferInputSource.hh

@@ -25,7 +25,7 @@
 #include <qpdf/Buffer.hh>
 #include <qpdf/InputSource.hh>
 
-class BufferInputSource: public InputSource
+class QPDF_DLL_CLASS BufferInputSource: public InputSource
 {
   public:
     // If own_memory is true, BufferInputSource will delete the buffer
@@ -54,7 +54,7 @@ class BufferInputSource: public InputSource
     virtual void unreadCh(char ch);
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class BufferInputSource;
 

include/qpdf/ClosedFileInputSource.hh

@@ -35,7 +35,7 @@
 
 class FileInputSource;
 
-class ClosedFileInputSource: public InputSource
+class QPDF_DLL_CLASS ClosedFileInputSource: public InputSource
 {
   public:
     QPDF_DLL
@@ -71,7 +71,7 @@ class ClosedFileInputSource: public InputSource
     void before();
     void after();
 
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class ClosedFileInputSource;
 

include/qpdf/FileInputSource.hh

@@ -24,7 +24,7 @@
 
 #include <qpdf/InputSource.hh>
 
-class FileInputSource: public InputSource
+class QPDF_DLL_CLASS FileInputSource: public InputSource
 {
   public:
     QPDF_DLL
@@ -54,7 +54,7 @@ class FileInputSource: public InputSource
     FileInputSource(FileInputSource const&) = delete;
     FileInputSource& operator=(FileInputSource const&) = delete;
 
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class FileInputSource;
 

include/qpdf/InputSource.hh

@@ -30,6 +30,9 @@
 #include <stdio.h>
 #include <string>
 
+// Remember to use QPDF_DLL_CLASS on anything derived from InputSource
+// so it will work with dynamic_cast across the shared object
+// boundary.
 class QPDF_DLL_CLASS InputSource
 {
   public:

include/qpdf/Pipeline.hh

@@ -50,6 +50,8 @@
 #include <memory>
 #include <string>
 
+// Remember to use QPDF_DLL_CLASS on anything derived from Pipeline so
+// it will work with dynamic_cast across the shared object boundary.
 class QPDF_DLL_CLASS Pipeline
 {
   public:

include/qpdf/Pl_Buffer.hh

@@ -39,7 +39,7 @@
 
 #include <memory>
 
-class Pl_Buffer: public Pipeline
+class QPDF_DLL_CLASS Pl_Buffer: public Pipeline
 {
   public:
     QPDF_DLL
@@ -71,7 +71,7 @@ class Pl_Buffer: public Pipeline
     void getMallocBuffer(unsigned char** buf, size_t* len);
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_Buffer;
 

include/qpdf/Pl_Concatenate.hh

@@ -30,7 +30,7 @@
 
 #include <qpdf/Pipeline.hh>
 
-class Pl_Concatenate: public Pipeline
+class QPDF_DLL_CLASS Pl_Concatenate: public Pipeline
 {
   public:
     QPDF_DLL
@@ -50,7 +50,7 @@ class Pl_Concatenate: public Pipeline
     void manualFinish();
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_Concatenate;
 

include/qpdf/Pl_Count.hh

@@ -28,7 +28,7 @@
 #include <qpdf/Pipeline.hh>
 #include <qpdf/Types.h>
 
-class Pl_Count: public Pipeline
+class QPDF_DLL_CLASS Pl_Count: public Pipeline
 {
   public:
     QPDF_DLL
@@ -48,7 +48,7 @@ class Pl_Count: public Pipeline
     unsigned char getLastChar() const;
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_Count;
 

include/qpdf/Pl_DCT.hh

@@ -31,7 +31,7 @@
 // definition of size_t.
 #include <jpeglib.h>
 
-class Pl_DCT: public Pipeline
+class QPDF_DLL_CLASS Pl_DCT: public Pipeline
 {
   public:
     // Constructor for decompressing image data
@@ -75,7 +75,7 @@ class Pl_DCT: public Pipeline
 
     enum action_e { a_compress, a_decompress };
 
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_DCT;
 

include/qpdf/Pl_Discard.hh

@@ -30,7 +30,7 @@
 
 #include <qpdf/Pipeline.hh>
 
-class Pl_Discard: public Pipeline
+class QPDF_DLL_CLASS Pl_Discard: public Pipeline
 {
   public:
     QPDF_DLL
@@ -43,7 +43,7 @@ class Pl_Discard: public Pipeline
     virtual void finish();
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_Discard;
 

include/qpdf/Pl_Flate.hh

@@ -26,7 +26,7 @@
 #include <functional>
 #include <memory>
 
-class Pl_Flate: public Pipeline
+class QPDF_DLL_CLASS Pl_Flate: public Pipeline
 {
   public:
     static unsigned int const def_bufsize = 65536;
@@ -65,7 +65,7 @@ class Pl_Flate: public Pipeline
     void checkError(char const* prefix, int error_code);
     void warn(char const*, int error_code);
 
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_Flate;
 

include/qpdf/Pl_QPDFTokenizer.hh

@@ -41,7 +41,7 @@
 // QPDFObjectHandle::addTokenFilter. See QPDFObjectHandle.hh for
 // details.
 
-class Pl_QPDFTokenizer: public Pipeline
+class QPDF_DLL_CLASS Pl_QPDFTokenizer: public Pipeline
 {
   public:
     // Whatever pipeline is provided as "next" will be set as the
@@ -60,7 +60,7 @@ class Pl_QPDFTokenizer: public Pipeline
     virtual void finish();
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_QPDFTokenizer;
 

include/qpdf/Pl_RunLength.hh

@@ -24,7 +24,7 @@
 
 #include <qpdf/Pipeline.hh>
 
-class Pl_RunLength: public Pipeline
+class QPDF_DLL_CLASS Pl_RunLength: public Pipeline
 {
   public:
     enum action_e { a_encode, a_decode };
@@ -46,7 +46,7 @@ class Pl_RunLength: public Pipeline
 
     enum state_e { st_top, st_copying, st_run };
 
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_RunLength;
 

include/qpdf/Pl_StdioFile.hh

@@ -32,7 +32,7 @@
 // This pipeline is reusable.
 //
 
-class Pl_StdioFile: public Pipeline
+class QPDF_DLL_CLASS Pl_StdioFile: public Pipeline
 {
   public:
     // f is externally maintained; this class just writes to and
@@ -48,7 +48,7 @@ class Pl_StdioFile: public Pipeline
     virtual void finish();
 
   private:
-    class Members
+    class QPDF_DLL_PRIVATE Members
     {
         friend class Pl_StdioFile;
 

qpdf/test_driver.cc

@@ -3,6 +3,7 @@
 
 #include <qpdf/QPDF.hh>
 
+#include <qpdf/BufferInputSource.hh>
 #include <qpdf/Pl_Buffer.hh>
 #include <qpdf/Pl_Discard.hh>
 #include <qpdf/Pl_Flate.hh>
@@ -2314,8 +2315,9 @@ test_60(QPDF& pdf, char const* arg2)
 static void
 test_61(QPDF& pdf, char const* arg2)
 {
-    // Test to make sure exceptions can be caught properly across
+    // Test to make sure type information is passed across shared
-    // shared library boundaries.
+    // library boundaries. This includes exception handling, dynamic
+    // cast, and subclassing.
     pdf.setAttemptRecovery(false);
     pdf.setSuppressWarnings(true);
     try {
@@ -2338,6 +2340,17 @@ test_61(QPDF& pdf, char const* arg2)
     } catch (std::runtime_error const&) {
         std::cout << "Caught runtime_error as expected" << std::endl;
     }
+
+    // Spot check RTTI for dynamic cast. We intend to have pipelines
+    // and input sources be testable, but adding comprehensive tests
+    // for everything doesn't add value as it wouldn't catch
+    // forgetting QPDF_DLL_CLASS on a new subclass.
+    BufferInputSource b("x", "y");
+    InputSource* is = &b;
+    assert(dynamic_cast<BufferInputSource*>(is) != nullptr);
+    Pl_Discard pd;
+    Pipeline* p = &pd;
+    assert(dynamic_cast<Pl_Discard*>(p) != nullptr);
 }
 
 static void