lib,src: fix a few typos in comments

tniessen · danielleadams · commit 7f9e60aa1ae9 · 2023-04-10T22:18:19.000-04:00
PR-URL: #46835 Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com> Reviewed-By: Richard Lau <rlau@redhat.com> Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
diff --git a/lib/_http_client.js b/lib/_http_client.js
@@ -786,8 +786,8 @@ function responseOnTimeout() {
   res.emit('timeout');
 }
 
-// This function is necessary in the case where we receive the entire reponse
-// from server before we finish sending out the request
+// This function is necessary in the case where we receive the entire response
+// from the server before we finish sending out the request.
 function requestOnFinish() {
   const req = this;
 
diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
@@ -426,7 +426,7 @@ function onerror(err) {
     // so self._tlsError will return null instead of actual error
 
     // Set closing the socket after emitting an event since the socket needs to
-    // be accessible when the `tlsClientError` event is emmited.
+    // be accessible when the `tlsClientError` event is emitted.
     owner._closeAfterHandlingError = true;
     owner.destroy(err);
   } else if (owner._tlsOptions?.isServer &&
diff --git a/src/base_object.h b/src/base_object.h
@@ -249,7 +249,7 @@ inline T* Unwrap(v8::Local<v8::Value> obj) {
 // reset to nullptr once the BaseObject is destroyed.
 // The API matches std::shared_ptr closely. However, this class is not thread
 // safe, that is, we can't have different BaseObjectPtrImpl instances in
-// different threads refering to the same BaseObject instance.
+// different threads referring to the same BaseObject instance.
 template <typename T, bool kIsWeak>
 class BaseObjectPtrImpl final {
  public:
diff --git a/src/dataqueue/queue.h b/src/dataqueue/queue.h
@@ -0,0 +1,294 @@
+#pragma once
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include <base_object.h>
+#include <memory_tracker.h>
+#include <node.h>
+#include <node_bob.h>
+#include <node_file.h>
+#include <stream_base.h>
+#include <uv.h>
+#include <v8.h>
+
+#include <memory>
+#include <optional>
+#include <vector>
+
+namespace node {
+
+// Represents a sequenced collection of data sources that can be
+// consumed as a single logical stream of data. Sources can be
+// memory-resident or streaming.
+//
+// There are two essential kinds of DataQueue:
+//
+// * Idempotent - Multiple reads always produce the same result.
+//                This is even the case if individual sources
+//                are not memory-resident. Reads never change
+//                the state of the DataQueue. Every entry in
+//                an Idempotent DataQueue must also be idempotent.
+//
+// * Non-idempotent - Reads are destructive of the internal state.
+//                    A non-idempotent DataQueue can be read at
+//                    most once and only by a single reader.
+//                    Entries in a non-idempotent DataQueue can
+//                    be a mix of idempotent and non-idempotent
+//                    entries.
+//
+// The DataQueue is essentially a collection of DataQueue::Entry
+// instances. A DataQueue::Entry is a single logical source of
+// data. The data may be memory-resident or streaming. The entry
+// can be idempotent or non-idempotent. An entry cannot be read
+// by itself, it must be part of a DataQueue to be consumed.
+//
+// Example of creating an idempotent DataQueue:
+//
+//   std::shared_ptr<v8::BackingStore> store1 = getBackingStoreSomehow();
+//   std::shared_ptr<v8::BackingStore> store2 = getBackingStoreSomehow();
+//
+//   std::vector<std::unique_ptr<DataQueue::Entry>> list;
+//   list.push_back(DataQueue::CreateInMemoryEntryFromBackingStore(
+//       store1, 0, len1));
+//   list.push_back(DataQueue::CreateInMemoryEntryFromBackingStore(
+//       store2, 0, len2));
+//
+//   std::shared_ptr<DataQueue> data_queue =
+//       DataQueue::CreateIdempotent(std::move(list));
+//
+// Importantly, idempotent DataQueue's are immutable and all entries
+// must be provided when the DataQueue is constructed. Every entry
+// must be idempotent with known sizes. The entries may be memory
+// resident or streaming. Streaming entries must be capable of
+// being read multiple times.
+//
+// Because idempotent DataQueue's will always produce the same results
+// when read, they can be sliced. Slices yield a new DataQueue instance
+// that is a subset view over the original:
+//
+//   std::shared_ptr<DataQueue> slice = data_queue.slice(
+//       5, v8::Just(10UL));
+//
+// Example of creating a non-idempotent DataQueue:
+//
+//   std::shared_ptr<v8::BackingStore> store1 = getBackingStoreSomehow();
+//   std::shared_ptr<v8::BackingStore> store2 = getBackingStoreSomehow();
+//
+//   std::shared_ptr<DataQueue> data_queue = DataQueue::Create();
+//
+//   data_queue->append(DataQueue::CreateInMemoryEntryFromBackingStore(
+//       store1, 0, len1));
+//
+//   data_queue->append(DataQueue::CreateInMemoryEntryFromBackingStore(
+//       store2, 0, len2));
+//
+// These data-queues can have new entries appended to them. Entries can
+// be memory-resident or streaming. Streaming entries might not have
+// a known size. Entries may not be capable of being read multiple
+// times.
+//
+// A non-idempotent data queue will, by default, allow any amount of
+// entries to be appended to it. To limit the size of the DataQueue,
+// or the close the DataQueue (preventing new entries from being
+// appending), use the cap() method. The DataQueue can be capped
+// at a specific size or whatever size it currently it.
+//
+// It might not be possible for a non-idempotent DataQueue to provide
+// a size because it might not know how much data a streaming entry
+// will ultimately provide.
+//
+// Non-idempotent DataQueues cannot be sliced.
+//
+// To read from a DataQueue, we use the node::bob::Source API
+// (see src/node_bob.h).
+//
+//   std::shared_ptr<DataQueue::Reader> reader = data_queue->get_reader();
+//
+//   reader->Pull(
+//        [](int status, const DataQueue::Vec* vecs,
+//           uint64_t count, Done done) {
+//     // status is one of node::bob::Status
+//     // vecs is zero or more data buffers containing the read data
+//     // count is the number of vecs
+//     // done is a callback to be invoked when done processing the data
+//   }, options, nullptr, 0, 16);
+//
+// Keep calling Pull() until status is equal to node::bob::Status::STATUS_EOS.
+//
+// For idempotent DataQueues, any number of readers can be created and
+// pull concurrently from the same DataQueue. The DataQueue can be read
+// multiple times. Successful reads should always produce the same result.
+// If, for whatever reason, the implementation cannot ensure that the
+// data read will remain the same, the read must fail with an error status.
+//
+// For non-idempotent DataQueues, only a single reader is ever allowed for
+// the DataQueue, and the data can only ever be read once.
+
+class DataQueue : public MemoryRetainer {
+ public:
+  struct Vec {
+    uint8_t* base;
+    uint64_t len;
+  };
+
+  // A DataQueue::Reader consumes the DataQueue. If the data queue is
+  // idempotent, multiple Readers can be attached to the DataQueue at
+  // any given time, all guaranteed to yield the same result when the
+  // data is read. Otherwise, only a single Reader can be attached.
+  class Reader : public MemoryRetainer, public bob::Source<Vec> {
+   public:
+    using Next = bob::Next<Vec>;
+    using Done = bob::Done;
+  };
+
+  // A DataQueue::Entry represents a logical chunk of data in the queue.
+  // The entry may or may not represent memory-resident data. It may
+  // or may not be consumable more than once.
+  class Entry : public MemoryRetainer {
+   public:
+    // Returns a new Entry that is a view over this entries data
+    // from the start offset to the ending offset. If the end
+    // offset is omitted, the slice extends to the end of the
+    // data.
+    //
+    // Creating a slice is only possible if is_idempotent() returns
+    // true. This is because consuming either the original entry or
+    // the new entry would change the state of the other in non-
+    // deterministic ways. When is_idempotent() returns false, slice()
+    // must return a nulled unique_ptr.
+    //
+    // Creating a slice is also only possible if the size of the
+    // entry is known. If size() returns std::nullopt, slice()
+    // must return a nulled unique_ptr.
+    virtual std::unique_ptr<Entry> slice(
+        uint64_t start, std::optional<uint64_t> end = std::nullopt) = 0;
+
+    // Returns the number of bytes represented by this Entry if it is
+    // known. Certain types of entries, such as those backed by streams
+    // might not know the size in advance and therefore cannot provide
+    // a value. In such cases, size() must return v8::Nothing<uint64_t>.
+    //
+    // If the entry is idempotent, a size should always be available.
+    virtual std::optional<uint64_t> size() const = 0;
+
+    // When true, multiple reads on the object must produce the exact
+    // same data or the reads will fail. Some sources of entry data,
+    // such as streams, may not be capable of preserving idempotency
+    // and therefore must not claim to be. If an entry claims to be
+    // idempotent and cannot preserve that quality, subsequent reads
+    // must fail with an error when a variance is detected.
+    virtual bool is_idempotent() const = 0;
+  };
+
+  // Creates an idempotent DataQueue with a pre-established collection
+  // of entries. All of the entries must also be idempotent otherwise
+  // an empty std::unique_ptr will be returned.
+  static std::shared_ptr<DataQueue> CreateIdempotent(
+      std::vector<std::unique_ptr<Entry>> list);
+
+  // Creates a non-idempotent DataQueue. This kind of queue can be
+  // mutated and updated such that multiple reads are not guaranteed
+  // to produce the same result. The entries added can be of any type.
+  static std::shared_ptr<DataQueue> Create(
+      std::optional<uint64_t> capped = std::nullopt);
+
+  // Creates an idempotent Entry from a v8::ArrayBufferView. To help
+  // ensure idempotency, the underlying ArrayBuffer is detached from
+  // the BackingStore. It is the callers responsibility to ensure that
+  // the BackingStore is not otherwise modified through any other
+  // means. If the ArrayBuffer is not detachable, nullptr will be
+  // returned.
+  static std::unique_ptr<Entry> CreateInMemoryEntryFromView(
+      v8::Local<v8::ArrayBufferView> view);
+
+  // Creates an idempotent Entry from a v8::BackingStore. It is the
+  // callers responsibility to ensure that the BackingStore is not
+  // otherwise modified through any other means. If the ArrayBuffer
+  // is not detachable, nullptr will be returned.
+  static std::unique_ptr<Entry> CreateInMemoryEntryFromBackingStore(
+      std::shared_ptr<v8::BackingStore> store,
+      uint64_t offset,
+      uint64_t length);
+
+  static std::unique_ptr<Entry> CreateDataQueueEntry(
+      std::shared_ptr<DataQueue> data_queue);
+
+  static std::unique_ptr<Entry> CreateFdEntry(Environment* env,
+                                              v8::Local<v8::Value> path);
+
+  // Creates a Reader for the given queue. If the queue is idempotent,
+  // any number of readers can be created, all of which are guaranteed
+  // to provide the same data. Otherwise, only a single reader is
+  // permitted.
+  virtual std::shared_ptr<Reader> get_reader() = 0;
+
+  // Append a single new entry to the queue. Appending is only allowed
+  // when is_idempotent() is false. std::nullopt will be returned
+  // if is_idempotent() is true. std::optional(false) will be returned if the
+  // data queue is not idempotent but the entry otherwise cannot be added.
+  virtual std::optional<bool> append(std::unique_ptr<Entry> entry) = 0;
+
+  // Caps the size of this DataQueue preventing additional entries to
+  // be added if those cause the size to extend beyond the specified
+  // limit.
+  //
+  // If limit is zero, or is less than the known current size of the
+  // data queue, the limit is set to the current known size, meaning
+  // that no additional entries can be added at all.
+  //
+  // If the size of the data queue is not known, the limit will be
+  // ignored and no additional entries will be allowed at all.
+  //
+  // If is_idempotent is true capping is unnecessary because the data
+  // queue cannot be appended to. In that case, cap() is a non-op.
+  //
+  // If the data queue has already been capped, cap can be called
+  // again with a smaller size.
+  virtual void cap(uint64_t limit = 0) = 0;
+
+  // Returns a new DataQueue that is a view over this queues data
+  // from the start offset to the ending offset. If the end offset
+  // is omitted, the slice extends to the end of the data.
+  //
+  // The slice will coverage a range from start up to, but excluding, end.
+  //
+  // Creating a slice is only possible if is_idempotent() returns
+  // true. This is because consuming either the original DataQueue or
+  // the new queue would change the state of the other in non-
+  // deterministic ways. When is_idempotent() returns false, slice()
+  // must return a nulled unique_ptr.
+  //
+  // Creating a slice is also only possible if the size of the
+  // DataQueue is known. If size() returns std::nullopt, slice()
+  // must return a null unique_ptr.
+  virtual std::shared_ptr<DataQueue> slice(
+      uint64_t start, std::optional<uint64_t> end = std::nullopt) = 0;
+
+  // The size of DataQueue is the total size of all of its member entries.
+  // If any of the entries is not able to specify a size, the DataQueue
+  // will also be incapable of doing so, in which case size() must return
+  // std::nullopt.
+  virtual std::optional<uint64_t> size() const = 0;
+
+  // A DataQueue is idempotent only if all of its member entries are
+  // idempotent.
+  virtual bool is_idempotent() const = 0;
+
+  // True only if cap is called or the data queue is a limited to a
+  // fixed size.
+  virtual bool is_capped() const = 0;
+
+  // If the data queue has been capped, and the size of the data queue
+  // is known, maybeCapRemaining will return the number of additional
+  // bytes the data queue can receive before reaching the cap limit.
+  // If the size of the queue cannot be known, or the cap has not
+  // been set, maybeCapRemaining() will return std::nullopt.
+  virtual std::optional<uint64_t> maybeCapRemaining() const = 0;
+
+  static void Initialize(Environment* env, v8::Local<v8::Object> target);
+  static void RegisterExternalReferences(ExternalReferenceRegistry* registry);
+};
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
diff --git a/src/node_contextify.cc b/src/node_contextify.cc
@@ -249,7 +249,7 @@ BaseObjectPtr<ContextifyContext> ContextifyContext::New(
     const ContextOptions& options) {
   HandleScope scope(env->isolate());
   // This only initializes part of the context. The primordials are
-  // only initilaized when needed because even deserializing them slows
+  // only initialized when needed because even deserializing them slows
   // things down significantly and they are only needed in rare occasions
   // in the vm contexts.
   if (InitializeContextRuntime(v8_context).IsNothing()) {
