add example handler

This adds an example handler to demonstrate how one can add a specific
type of BLOB handler.

Change-Id: Ib5421f1b945b45998b40d3939a4dab9cdf39aaa9
Signed-off-by: Patrick Venture <venture@google.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/example/example.hpp b/example/example.hpp
new file mode 100644
index 0000000..0ea9572
--- /dev/null
+++ b/example/example.hpp
@@ -0,0 +1,71 @@
+#pragma once
+
+#include "blobs.hpp"
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace blobs
+{
+
+constexpr int kBufferSize = 1024;
+
+struct ExampleBlob
+{
+    ExampleBlob() = default;
+    ExampleBlob(uint16_t id, uint16_t flags) :
+        sessionId(id), flags(flags), length(0)
+    {
+    }
+
+    /* The blob handler session id. */
+    uint16_t sessionId;
+
+    /* The flags passed into open. */
+    uint16_t flags;
+
+    /* The buffer is a fixed size, but length represents the number of bytes
+     * expected to be used contiguously from offset 0.
+     */
+    uint32_t length;
+
+    /* The staging buffer. */
+    uint8_t buffer[kBufferSize];
+};
+
+class ExampleBlobHandler : public GenericBlobInterface
+{
+  public:
+    /* We want everything explicitly default. */
+    ExampleBlobHandler() = default;
+    ~ExampleBlobHandler() = default;
+    ExampleBlobHandler(const ExampleBlobHandler&) = default;
+    ExampleBlobHandler& operator=(const ExampleBlobHandler&) = default;
+    ExampleBlobHandler(ExampleBlobHandler&&) = default;
+    ExampleBlobHandler& operator=(ExampleBlobHandler&&) = default;
+
+    bool canHandleBlob(const std::string& path) override;
+    std::vector<std::string> getBlobIds() override;
+    bool deleteBlob(const std::string& path) override;
+    bool stat(const std::string& path, struct BlobMeta* meta) override;
+    bool open(uint16_t session, uint16_t flags,
+              const std::string& path) override;
+    std::vector<uint8_t> read(uint16_t session, uint32_t offset,
+                              uint32_t requestedSize) override;
+    bool write(uint16_t session, uint32_t offset,
+               const std::vector<uint8_t>& data) override;
+    bool commit(uint16_t session, const std::vector<uint8_t>& data) override;
+    bool close(uint16_t session) override;
+    bool stat(uint16_t session, struct BlobMeta* meta) override;
+    bool expire(uint16_t session) override;
+
+    constexpr static char supportedPath[] = "/dev/fake/command";
+
+  private:
+    ExampleBlob* getSession(uint16_t id);
+
+    std::unordered_map<uint16_t, ExampleBlob> sessions;
+};
+
+} // namespace blobs