WIP: NSS trust store integration for path builder.

net/cert/internal/cert_issuer_source_collection.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/cert/internal/cert_issuer_source_collection.h"
+
+#include <unordered_map>
+
+#include "base/bind.h"
+#include "net/cert/internal/parsed_certificate.h"
+
+namespace net {
+
+namespace {
+
+using RequestSet =
+    std::unordered_map<CertIssuerSource::Request*,
+                       std::unique_ptr<CertIssuerSource::Request>>;
+
+class CollectionRequest : public CertIssuerSource::Request {
+ public:
+  explicit CollectionRequest(
+      const CertIssuerSource::IssuerCallback& issuers_callback);
+  ~CollectionRequest() override;
+
+  // CertIssuerSource::Request implementation.
+  CompletionStatus GetNext(scoped_refptr<ParsedCertificate>* out_cert) override;
+
+  void MakeRequest(scoped_refptr<ParsedCertificate> cert,
+                   CertIssuerSource* source);
+  bool has_requests() const {
+    return !pending_requests_.empty() || !ready_requests_.empty();
+  }
+
+ private:
+  void OnAsyncGetIssuersOf(CertIssuerSource::Request* req);
+
+  CertIssuerSource::IssuerCallback issuers_callback_;
+
+  RequestSet pending_requests_;
+  RequestSet ready_requests_;
+
+  DISALLOW_COPY_AND_ASSIGN(CollectionRequest);
+};
+
+CollectionRequest::CollectionRequest(
+    const CertIssuerSource::IssuerCallback& issuers_callback)
+    : issuers_callback_(issuers_callback) {}
+
+CollectionRequest::~CollectionRequest() = default;
+
+CompletionStatus CollectionRequest::GetNext(
+    scoped_refptr<ParsedCertificate>* out_cert) {
+  while (!ready_requests_.empty()) {
+    auto it = ready_requests_.begin();
+    CompletionStatus status = it->second->GetNext(out_cert);
+    if (status == CompletionStatus::ASYNC) {
+      // This Request has no more results ready, but isn't done yet. Move it
+      // back to the pending list.
+      pending_requests_[it->first] = std::move(it->second);
+      ready_requests_.erase(it);
+    } else if (!*out_cert) {
+      // This Request is done, remove it.
+      ready_requests_.erase(it);
+    } else {
+      // This Request returned a result, pass it on.
+      return CompletionStatus::SYNC;
+    }
+    // No result from that Request, loop around try another.
+  }
+
+  *out_cert = nullptr;
+  if (!pending_requests_.empty()) {
+    // No results available at the moment, but there are still pending Requests.
+    return CompletionStatus::ASYNC;
+  }
+
+  // All Requests are complete.
+  return CompletionStatus::SYNC;
+}
+
+void CollectionRequest::MakeRequest(scoped_refptr<ParsedCertificate> cert,
+                                    CertIssuerSource* source) {
+  std::unique_ptr<CertIssuerSource::Request> req;
+  source->AsyncGetIssuersOf(std::move(cert),
+                            base::Bind(&CollectionRequest::OnAsyncGetIssuersOf,
+                                       base::Unretained(this)),
+                            &req);
+  if (req) {
+    CertIssuerSource::Request* req_ptr = req.get();
+    pending_requests_[req_ptr] = std::move(req);
+  }
+}
+
+void CollectionRequest::OnAsyncGetIssuersOf(CertIssuerSource::Request* req) {
+  bool client_waiting_for_callback = ready_requests_.empty();
+  // Find the request which just returned some results and move it to the ready
+  // list, if it isn't there already.
+  auto it = pending_requests_.find(req);
+  if (it != pending_requests_.end()) {
+    ready_requests_[it->first] = std::move(it->second);
+    pending_requests_.erase(it);
+    // Notify the client that results are now available.
+    if (client_waiting_for_callback)
+      issuers_callback_.Run(this);
+  } else {
+    // If it wasn't in the pending requests, it must already be in the ready
+    // requests.
+    DCHECK(ready_requests_.count(req));
+  }
+}
+
+}  // namespace
+
+CertIssuerSourceCollection::CertIssuerSourceCollection() = default;
+CertIssuerSourceCollection::~CertIssuerSourceCollection() = default;
+
+void CertIssuerSourceCollection::AddSource(CertIssuerSource* source) {
+  sources_.push_back(source);
+}
+
+void CertIssuerSourceCollection::SyncGetIssuersOf(
+    const ParsedCertificate* cert,
+    ParsedCertificateList* issuers) {
+  for (CertIssuerSource* source : sources_)
+    source->SyncGetIssuersOf(cert, issuers);
+}
+
+void CertIssuerSourceCollection::AsyncGetIssuersOf(
+    scoped_refptr<ParsedCertificate> cert,
+    const IssuerCallback& issuers_callback,
+    std::unique_ptr<Request>* out_req) {
+  std::unique_ptr<CollectionRequest> req(
+      new CollectionRequest(issuers_callback));
+
+  for (CertIssuerSource* source : sources_)
+    req->MakeRequest(cert, source);
+
+  if (req->has_requests())
+    *out_req = std::move(req);
+  else
+    out_req->reset();
+}
+
+}  // namespace net