Fix creation of Altium compound files from IntLibs

A previous change introduced an invalid cast from
base to derived class.  To clean this up, changed
DecodeIntLibStream to have an out param and allow
two-step initialization of ALTIUM_COMPOUND_FILE

Fixes https://gitlab.com/kicad/code/kicad/-/issues/20099

common/io/altium/altium_binary_parser.cpp

@@ -47,6 +47,11 @@ std::string FormatPath( const std::vector<std::string>& aVectorPath )
 }
 
 
+ALTIUM_COMPOUND_FILE::ALTIUM_COMPOUND_FILE()
+{
+}
+
+
 ALTIUM_COMPOUND_FILE::ALTIUM_COMPOUND_FILE( const wxString& aFilePath )
 {
     // Open file
@@ -91,6 +96,12 @@ ALTIUM_COMPOUND_FILE::ALTIUM_COMPOUND_FILE( const wxString& aFilePath )
 
 
 ALTIUM_COMPOUND_FILE::ALTIUM_COMPOUND_FILE( const void* aBuffer, size_t aLen )
+{
+    InitFromBuffer( aBuffer, aLen );
+}
+
+
+void ALTIUM_COMPOUND_FILE::InitFromBuffer( const void* aBuffer, size_t aLen )
 {
     m_buffer.resize( aLen );
     memcpy( m_buffer.data(), aBuffer, aLen );
@@ -106,10 +117,11 @@ ALTIUM_COMPOUND_FILE::ALTIUM_COMPOUND_FILE( const void* aBuffer, size_t aLen )
 }
 
 
-std::unique_ptr<ALTIUM_COMPOUND_FILE>
-ALTIUM_COMPOUND_FILE::DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe )
+bool ALTIUM_COMPOUND_FILE::DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe,
+                                               ALTIUM_COMPOUND_FILE* aOutput )
 {
-    wxCHECK( cfe.size >= 1, nullptr );
+    wxCHECK( aOutput, false );
+    wxCHECK( cfe.size >= 1, false );
 
     size_t         streamSize = cfe.size;
     wxMemoryBuffer buffer( streamSize );
@@ -130,14 +142,13 @@ ALTIUM_COMPOUND_FILE::DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe )
         decodedPcbLibStream << zlibInputStream;
 
         wxStreamBuffer* outStream = decodedPcbLibStream.GetOutputStreamBuffer();
-
-        return std::make_unique<ALTIUM_COMPOUND_FILE>( outStream->GetBufferStart(),
-                                                       outStream->GetIntPosition() );
+        aOutput->InitFromBuffer( outStream->GetBufferStart(), outStream->GetIntPosition() );
+        return true;
     }
     else if( buffer[0] == 0x00 )
     {
-        return std::make_unique<ALTIUM_COMPOUND_FILE>(
-                reinterpret_cast<uint8_t*>( buffer.GetData() ) + 1, streamSize - 1 );
+        aOutput->InitFromBuffer( static_cast<uint8_t*>( buffer.GetData() ) + 1, streamSize - 1 );
+        return true;
     }
     else
     {
@@ -145,7 +156,7 @@ ALTIUM_COMPOUND_FILE::DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe )
                                       buffer[0], buffer[1], buffer[2], buffer[3], buffer[4] ) );
     }
 
-    return nullptr;
+    return false;
 }
 
 

common/io/altium/altium_binary_parser.h

@@ -70,6 +70,9 @@ class ALTIUM_COMPOUND_FILE
     friend class ALTIUM_PCB_COMPOUND_FILE;
 
 public:
+    /// Create an uninitialized file for two-step initialization (e.g. with InitFromBuffer)
+    ALTIUM_COMPOUND_FILE();
+
     /**
      * Open a CFB file. Constructor might throw an IO_ERROR.
      *
@@ -90,9 +93,18 @@ public:
     ALTIUM_COMPOUND_FILE& operator=( const ALTIUM_COMPOUND_FILE& temp_obj ) = delete;
     ~ALTIUM_COMPOUND_FILE() = default;
 
+    /**
+     * Load a CFB file from memory; may throw an IO_ERROR.
+     * Data is copied.
+     *
+     * @param aBuffer data buffer
+     * @param aLen data length
+     */
+    void InitFromBuffer( const void* aBuffer, size_t aLen );
+
     const CFB::CompoundFileReader& GetCompoundFileReader() const { return *m_reader; }
 
-    std::unique_ptr<ALTIUM_COMPOUND_FILE> DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe );
+    bool DecodeIntLibStream( const CFB::COMPOUND_FILE_ENTRY& cfe, ALTIUM_COMPOUND_FILE* aOutput );
 
     const CFB::COMPOUND_FILE_ENTRY* FindStream( const std::vector<std::string>& aStreamPath ) const;
 

pcbnew/pcb_io/altium/altium_pcb_compound_file.h

@@ -32,6 +32,8 @@
 class ALTIUM_PCB_COMPOUND_FILE : public ALTIUM_COMPOUND_FILE
 {
 public:
+    ALTIUM_PCB_COMPOUND_FILE() : ALTIUM_COMPOUND_FILE() {}
+
     ALTIUM_PCB_COMPOUND_FILE( const wxString& aFilePath );
     ALTIUM_PCB_COMPOUND_FILE( const void* aBuffer, size_t aLen );
     ~ALTIUM_PCB_COMPOUND_FILE();

pcbnew/pcb_io/altium/pcb_io_altium_designer.cpp

@@ -197,14 +197,13 @@ void PCB_IO_ALTIUM_DESIGNER::loadAltiumLibrary( const wxString& aLibraryPath )
 
             std::map<wxString, const CFB::COMPOUND_FILE_ENTRY*> pcbLibFiles =
                     intCom->EnumDir( L"PCBLib" );
+
             for( const auto& [pcbLibName, pcbCfe] : pcbLibFiles )
             {
-                auto decodedStream = intCom->DecodeIntLibStream( *pcbCfe );
-                m_fplibFiles[aLibraryPath].push_back(
-                    std::unique_ptr<ALTIUM_PCB_COMPOUND_FILE>(
-                        static_cast<ALTIUM_PCB_COMPOUND_FILE*>(decodedStream.release())
-                    )
-                );
+                auto decodedStream = std::make_unique<ALTIUM_PCB_COMPOUND_FILE>();
+
+                if( intCom->DecodeIntLibStream( *pcbCfe, decodedStream.get() ) )
+                    m_fplibFiles[aLibraryPath].emplace_back( std::move( decodedStream ) );
             }
         }
     }