Switch intro example to blobstore client
diff --git a/demo/src/blobstore.cc b/demo/src/blobstore.cc
new file mode 100644
index 0000000..a75affc
--- /dev/null
+++ b/demo/src/blobstore.cc
@@ -0,0 +1,71 @@
+#include "demo/include/blobstore.h"
+#include "demo/src/main.rs.h"
+#include <algorithm>
+#include <functional>
+#include <set>
+#include <string>
+#include <unordered_map>
+
+namespace org {
+namespace blobstore {
+
+// Toy implementation of an in-memory blobstore.
+//
+// In reality the implementation of BlobstoreClient could be a large complex C++
+// library.
+class BlobstoreClient::impl {
+ friend BlobstoreClient;
+ using Blob = struct {
+ std::string data;
+ std::set<std::string> tags;
+ };
+ std::unordered_map<uint64_t, Blob> blobs;
+};
+
+BlobstoreClient::BlobstoreClient() : impl(new typename BlobstoreClient::impl) {}
+
+// Upload a new blob and return a blobid that serves as a handle to the blob.
+uint64_t BlobstoreClient::put(MultiBuf &buf) const {
+ std::string contents;
+
+ // Traverse the caller's chunk iterator.
+ //
+ // In reality there might be sophisticated batching of chunks and/or parallel
+ // upload implemented by the blobstore's C++ client.
+ while (true) {
+ auto chunk = next_chunk(buf);
+ if (chunk.size() == 0) {
+ break;
+ }
+ contents.append(reinterpret_cast<const char *>(chunk.data()), chunk.size());
+ }
+
+ // Insert into map and provide caller the handle.
+ auto blobid = std::hash<std::string>{}(contents);
+ impl->blobs[blobid] = {std::move(contents), {}};
+ return blobid;
+}
+
+// Add tag to an existing blob.
+void BlobstoreClient::tag(uint64_t blobid, rust::Str tag) const {
+ impl->blobs[blobid].tags.emplace(tag);
+}
+
+// Retrieve metadata about a blob.
+BlobMetadata BlobstoreClient::metadata(uint64_t blobid) const {
+ BlobMetadata metadata{};
+ auto blob = impl->blobs.find(blobid);
+ if (blob != impl->blobs.end()) {
+ metadata.size = blob->second.data.size();
+ std::for_each(blob->second.tags.begin(), blob->second.tags.end(),
+ [&](auto &t) { metadata.tags.emplace_back(t); });
+ }
+ return metadata;
+}
+
+std::unique_ptr<BlobstoreClient> new_blobstore_client() {
+ return std::make_unique<BlobstoreClient>();
+}
+
+} // namespace blobstore
+} // namespace org