[ledger_client] Add fit::promise<> wrappers for some common Ledger API calls.
These wrappers turn various Page and PageSnapshot calls into
fit::promise<> equivalents. Where a ledger.Status is returned, an OK
status is translated into an ok() result, and any other value is
translated into an error() result.
TEST=future CLs exercise these methods
Change-Id: I556cb1267edad4d0284a16c9e3b07def71837dc2
diff --git a/lib/ledger_client/BUILD.gn b/lib/ledger_client/BUILD.gn
index 5a92952..b23fdd6 100644
--- a/lib/ledger_client/BUILD.gn
+++ b/lib/ledger_client/BUILD.gn
@@ -7,6 +7,7 @@
":constants",
":operations",
":page_client",
+ ":promise",
":types",
]
}
@@ -57,6 +58,17 @@
]
}
+source_set("promise") {
+ sources = [
+ "promise.h",
+ ]
+
+ public_deps = [
+ "//peridot/lib/fidl:array_to_string",
+ "//peridot/public/fidl/fuchsia.ledger",
+ ]
+}
+
source_set("status") {
sources = [
"status.cc",
diff --git a/lib/ledger_client/promise.h b/lib/ledger_client/promise.h
new file mode 100644
index 0000000..4947d75
--- /dev/null
+++ b/lib/ledger_client/promise.h
@@ -0,0 +1,136 @@
+// Copyright 2018 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#pragma once
+
+#include <fuchsia/ledger/cpp/fidl.h>
+#include <lib/fit/bridge.h>
+#include <lib/fit/promise.h>
+
+#include "peridot/lib/fidl/array_to_string.h" // for to_string(), to_array()
+
+namespace modular {
+
+// fit::promise wrapper functions for fuchsia.ledger.Page.
+//
+// These methods match the signatures in fuchsia.ledger.Page with the exception
+// that the first parameter is always a fuchsia::ledger::Page*.
+class PagePromise {
+ public:
+ static fit::promise<> StartTransaction(fuchsia::ledger::Page* page) {
+ fit::bridge<> bridge;
+ page->StartTransaction([completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status) mutable {
+ if (status == fuchsia::ledger::Status::OK) {
+ completer.complete_ok();
+ } else {
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+
+ static fit::promise<> Commit(fuchsia::ledger::Page* page) {
+ fit::bridge<> bridge;
+ page->Commit([completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status) mutable {
+ if (status == fuchsia::ledger::Status::OK) {
+ completer.complete_ok();
+ } else {
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+
+ static fit::promise<> Rollback(fuchsia::ledger::Page* page) {
+ fit::bridge<> bridge;
+ page->Commit([completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status) mutable {
+ if (status == fuchsia::ledger::Status::OK) {
+ completer.complete_ok();
+ } else {
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+
+ static fit::promise<> GetSnapshot(
+ fuchsia::ledger::Page* page,
+ fidl::InterfaceRequest<fuchsia::ledger::PageSnapshot> request) {
+ fit::bridge<> bridge;
+ page->GetSnapshot(std::move(request),
+ fidl::VectorPtr<uint8_t>::New(0) /* key_prefix */,
+ nullptr /* watcher */,
+ [completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status) mutable {
+ if (status == fuchsia::ledger::Status::OK) {
+ completer.complete_ok();
+ } else {
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+
+ static fit::promise<> Put(fuchsia::ledger::Page* page, std::string key,
+ std::vector<uint8_t> value) {
+ fit::bridge<> bridge;
+ page->Put(to_array(key), fidl::VectorPtr<uint8_t>(std::move(value)),
+ [completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status) mutable {
+ if (status == fuchsia::ledger::Status::OK) {
+ completer.complete_ok();
+ } else {
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+};
+
+// fit::promise wrapper functions for fuchsia.ledger.Page.
+//
+// These methods match the signatures in fuchsia.ledger.Page with the exception
+// that the first parameter is always a fuchsia::ledger::Page*.
+class PageSnapshotPromise {
+ public:
+ // fit::promise wrapper function for PageSnapshot.GetInline().
+ //
+ // Falls back to PageSnapshot::Get() if the value is too large.
+ // TODO(thatguy): Implement the fallback.
+ static fit::promise<std::unique_ptr<std::vector<uint8_t>>> GetInline(
+ fuchsia::ledger::PageSnapshot* snapshot, std::string key) {
+ fit::bridge<std::unique_ptr<std::vector<uint8_t>>> bridge;
+ snapshot->GetInline(
+ to_array(key), [completer = std::move(bridge.completer)](
+ fuchsia::ledger::Status status,
+ fuchsia::ledger::InlinedValuePtr value) mutable {
+ switch (status) {
+ case fuchsia::ledger::Status::OK:
+ case fuchsia::ledger::Status::KEY_NOT_FOUND:
+ if (value) {
+ // Convert the result to a unique_ptr instead of a VectorPtr.
+ auto ret =
+ std::make_unique<std::vector<uint8_t>>(value->value.take());
+ completer.complete_ok(std::move(ret));
+ } else {
+ completer.complete_ok(nullptr);
+ }
+ break;
+ case fuchsia::ledger::Status::VALUE_TOO_LARGE:
+ // TODO(thatguy): Handle a too-large value.
+ FXL_LOG(FATAL) << "TODO: fallback to PageSnapshot_Get().";
+ default:
+ FXL_LOG(ERROR) << "PageSnapshotPromise::GetInline() failed with "
+ << fidl::ToUnderlying(status);
+ completer.complete_error();
+ }
+ });
+ return bridge.consumer.promise();
+ }
+};
+
+} // namespace modular
