QPDFCryptoProvider: initial implementation

include/qpdf/QPDFCryptoImpl.hh

@@ -0,0 +1,44 @@
+// Copyright (c) 2005-2019 Jay Berkenbilt
+//
+// This file is part of qpdf.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Versions of qpdf prior to version 7 were released under the terms
+// of version 2.0 of the Artistic License. At your option, you may
+// continue to consider qpdf to be licensed under those terms. Please
+// see the manual for additional information.
+
+#ifndef QPDFCRYPTOIMPL_HH
+#define QPDFCRYPTOIMPL_HH
+
+#include <qpdf/DLL.h>
+
+// This class is part of qpdf's pluggable crypto provider support.
+// Most users won't need to know or care about this class, but you can
+// use it if you want to supply your own crypto implementation. To do
+// so, provide an implementation of QPDFCryptoImpl, ensure that you
+// register it by calling QPDFCryptoProvider::registerImpl, and make
+// it the default by calling QPDFCryptoProvider::setDefaultProvider.
+
+class QPDF_DLL_CLASS QPDFCryptoImpl
+{
+  public:
+    QPDF_DLL
+    QPDFCryptoImpl() = default;
+
+    QPDF_DLL
+    virtual ~QPDFCryptoImpl() = default;
+};
+
+#endif // QPDFCRYPTOIMPL_HH

include/qpdf/QPDFCryptoProvider.hh

@@ -0,0 +1,102 @@
+// Copyright (c) 2005-2019 Jay Berkenbilt
+//
+// This file is part of qpdf.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Versions of qpdf prior to version 7 were released under the terms
+// of version 2.0 of the Artistic License. At your option, you may
+// continue to consider qpdf to be licensed under those terms. Please
+// see the manual for additional information.
+
+#ifndef QPDFCRYPTOPROVIDER_HH
+#define QPDFCRYPTOPROVIDER_HH
+
+#include <qpdf/DLL.h>
+#include <qpdf/QPDFCryptoImpl.hh>
+#include <string>
+#include <map>
+#include <memory>
+#include <functional>
+
+// This class is part of qpdf's pluggable crypto provider support.
+// Most users won't need to know or care about this class, but you can
+// use it if you want to supply your own crypto implementation. See
+// also comments in QPDFCryptoImpl.hh.
+
+class QPDFCryptoProvider
+{
+  public:
+
+    // Methods for getting and registering crypto implementations.
+    // These methods are not thread-safe.
+
+    // Return an instance of a crypto provider using the default
+    // implementation.
+    QPDF_DLL
+    static std::shared_ptr<QPDFCryptoImpl> getImpl();
+
+    // Return an instance of the crypto provider registered using the
+    // given name.
+    QPDF_DLL
+    static std::shared_ptr<QPDFCryptoImpl>
+    getImpl(std::string const& name);
+
+    // Register the given type (T) as a crypto implementation. T must
+    // be derived from QPDFCryptoImpl and must have a constructor that
+    // takes no arguments.
+    template<typename T>
+    QPDF_DLL
+    static void registerImpl(std::string const& name);
+
+    // Set the crypto provider registered with the given name as the
+    // default crypto implementation.
+    QPDF_DLL
+    static void setDefaultProvider(std::string const& name);
+
+  private:
+    QPDFCryptoProvider();
+    ~QPDFCryptoProvider() = default;
+    QPDFCryptoProvider(QPDFCryptoProvider const&) = delete;
+    QPDFCryptoProvider& operator=(QPDFCryptoProvider const&) = delete;
+
+    static QPDFCryptoProvider& getInstance();
+
+    std::shared_ptr<QPDFCryptoImpl>
+    getImpl_internal(std::string const& name) const;
+    template<typename T>
+    void registerImpl_internal(std::string const& name);
+    void setDefaultProvider_internal(std::string const& name);
+
+    class Members
+    {
+        friend class QPDFCryptoProvider;
+
+      public:
+        Members() = default;
+        QPDF_DLL
+        ~Members() = default;
+
+      private:
+        Members(Members const&) = delete;
+        Members& operator=(Members const&) = delete;
+
+        typedef std::function<std::shared_ptr<QPDFCryptoImpl> ()> provider_fn;
+        std::string default_provider;
+        std::map<std::string, provider_fn> providers;
+    };
+
+    std::shared_ptr<Members> m;
+};
+
+#endif // QPDFCRYPTOPROVIDER_HH

libqpdf/QPDFCryptoProvider.cc

@@ -0,0 +1,76 @@
+#include <qpdf/QPDFCryptoProvider.hh>
+#include <stdexcept>
+
+#include <qpdf/QPDFCrypto_native.hh>
+
+std::shared_ptr<QPDFCryptoImpl>
+QPDFCryptoProvider::getImpl()
+{
+    QPDFCryptoProvider& p = getInstance();
+    if (p.m->default_provider.empty())
+    {
+        throw std::logic_error(
+            "QPDFCryptoProvider::getImpl called with no default provider.");
+    }
+    return p.getImpl_internal(p.m->default_provider);
+}
+
+std::shared_ptr<QPDFCryptoImpl>
+QPDFCryptoProvider::getImpl(std::string const& name)
+{
+    return getInstance().getImpl_internal(name);
+}
+
+template<typename T>
+void
+QPDFCryptoProvider::registerImpl(std::string const& name)
+{
+    getInstance().registerImpl_internal<T>(name);
+}
+
+void
+QPDFCryptoProvider::setDefaultProvider(std::string const& name)
+{
+    getInstance().setDefaultProvider_internal(name);
+}
+
+QPDFCryptoProvider::QPDFCryptoProvider() :
+    m(std::make_shared<Members>())
+{
+    registerImpl_internal<QPDFCrypto_native>("native");
+    setDefaultProvider_internal("native");
+}
+
+QPDFCryptoProvider&
+QPDFCryptoProvider::getInstance()
+{
+    static QPDFCryptoProvider instance;
+    return instance;
+}
+
+std::shared_ptr<QPDFCryptoImpl>
+QPDFCryptoProvider::getImpl_internal(std::string const& name) const
+{
+    auto iter = this->m->providers.find(name);
+    if (iter == this->m->providers.end())
+    {
+        throw std::logic_error(
+            "QPDFCryptoProvider requested unknown implementation \"" +
+            name + "\"");
+    }
+    return this->m->providers[name]();
+}
+
+template<typename T>
+void
+QPDFCryptoProvider::registerImpl_internal(std::string const& name)
+{
+    this->m->providers[name] = std::make_shared<T>;
+
+}
+
+void
+QPDFCryptoProvider::setDefaultProvider_internal(std::string const& name)
+{
+    this->m->default_provider = name;
+}

libqpdf/QPDFCrypto_native.cc

@@ -0,0 +1 @@
+#include <qpdf/QPDFCrypto_native.hh>

libqpdf/build.mk

@@ -39,6 +39,8 @@ SRCS_libqpdf = \
 	libqpdf/QPDF.cc \
 	libqpdf/QPDFAcroFormDocumentHelper.cc \
 	libqpdf/QPDFAnnotationObjectHelper.cc \
+	libqpdf/QPDFCryptoProvider.cc \
+	libqpdf/QPDFCrypto_native.cc \
 	libqpdf/QPDFExc.cc \
 	libqpdf/QPDFFormFieldObjectHelper.cc \
 	libqpdf/QPDFMatrix.cc \

libqpdf/qpdf/QPDFCrypto_native.hh

@@ -0,0 +1,16 @@
+#ifndef QPDFCRYPTO_NATIVE_HH
+#define QPDFCRYPTO_NATIVE_HH
+
+#include <qpdf/DLL.h>
+#include <qpdf/QPDFCryptoImpl.hh>
+
+class QPDFCrypto_native: public QPDFCryptoImpl
+{
+  public:
+    QPDFCrypto_native() = default;
+
+    QPDF_DLL
+    virtual ~QPDFCrypto_native() = default;
+};
+
+#endif // QPDFCRYPTO_NATIVE_HH