tools/pci: add wrapper for libpciaccess

This allows unit testing code that uses libpciaccess.

Signed-off-by: Benjamin Fair <benjaminfair@google.com>
Change-Id: Iec559c72e0e7b6c2e8737a54bb3e88fe1e0f4fdb
diff --git a/tools/pciaccess.hpp b/tools/pciaccess.hpp
new file mode 100644
index 0000000..ea7d5b4
--- /dev/null
+++ b/tools/pciaccess.hpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2020 Google Inc.
+ *
+ * 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.
+ */
+
+#pragma once
+
+extern "C"
+{
+#include <pciaccess.h>
+} // extern "C"
+
+namespace host_tool
+{
+
+/**
+ * @class PciAccess
+ * @brief Overridable interface to libpciacess for unit testing
+ */
+class PciAccess
+{
+  public:
+    virtual struct pci_device_iterator* pci_id_match_iterator_create(
+        const struct pci_id_match* match) const = 0;
+    virtual void
+        pci_iterator_destroy(struct pci_device_iterator* iter) const = 0;
+    virtual struct pci_device*
+        pci_device_next(struct pci_device_iterator* iter) const = 0;
+    virtual int pci_device_probe(struct pci_device* dev) const = 0;
+    virtual int pci_device_map_range(struct pci_device* dev, pciaddr_t base,
+                                     pciaddr_t size, unsigned map_flags,
+                                     void** addr) const = 0;
+    virtual int pci_device_unmap_range(struct pci_device* dev, void* memory,
+                                       pciaddr_t size) const = 0;
+
+    virtual ~PciAccess() = default;
+};
+
+/**
+ * @class PciAccessImpl
+ * @brief libpciaccess concrete implementation
+ * @details Passes through all calls to the underlying library.
+ */
+class PciAccessImpl : public PciAccess
+{
+  public:
+    struct pci_device_iterator* pci_id_match_iterator_create(
+        const struct pci_id_match* match) const override;
+    void pci_iterator_destroy(struct pci_device_iterator* iter) const override;
+    struct pci_device*
+        pci_device_next(struct pci_device_iterator* iter) const override;
+    int pci_device_probe(struct pci_device* dev) const override;
+    int pci_device_map_range(struct pci_device* dev, pciaddr_t base,
+                             pciaddr_t size, unsigned map_flags,
+                             void** addr) const override;
+    int pci_device_unmap_range(struct pci_device* dev, void* memory,
+                               pciaddr_t size) const override;
+
+    static PciAccessImpl& getInstance()
+    {
+        static PciAccessImpl instance;
+        return instance;
+    }
+
+  private:
+    PciAccessImpl();
+    virtual ~PciAccessImpl();
+};
+
+} // namespace host_tool