pw_stream: Provide default read/write limit functions
- Have default ConservativeReadLimit and ConservativeWriteLimit
functions that return std::numeric_limits<size_t>::max().
- Add a NullReader to accompany the NullWriter
- Add tests for the default read/write limit functions.
Change-Id: Id211dbc1ceef2f4f0046e936749b989516484e9f
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/26765
Reviewed-by: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
Commit-Queue: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
diff --git a/pw_stream/BUILD b/pw_stream/BUILD
index 242d460..996c044 100644
--- a/pw_stream/BUILD
+++ b/pw_stream/BUILD
@@ -24,15 +24,14 @@
pw_cc_library(
name = "pw_stream",
- hdrs = [
- "public/pw_stream/buffered_stream.h",
- "public/pw_stream/memory_stream.h",
- "public/pw_stream/null_stream.h",
- "public/pw_stream/stream.h",
- ],
srcs = [
- "memory_stream.cc",
- "buffered_stream.cc",
+ "buffered_stream.cc",
+ "memory_stream.cc",
+ ],
+ hdrs = [
+ "public/pw_stream/memory_stream.h",
+ "public/pw_stream/null_stream.h",
+ "public/pw_stream/stream.h",
],
includes = ["public"],
deps = [
@@ -49,8 +48,8 @@
srcs = ["socket_stream.cc"],
hdrs = ["public/pw_stream/socket_stream.h"],
deps = [
- "//pw_sys_io",
"//pw_stream",
+ "//pw_sys_io",
],
)
@@ -58,8 +57,8 @@
name = "pw_stream_sys_io",
hdrs = ["public/pw_stream/sys_io_stream.h"],
deps = [
- "//pw_sys_io",
"//pw_stream",
+ "//pw_sys_io",
],
)
@@ -75,9 +74,9 @@
)
pw_cc_test(
- name = "buffered_stream_test",
+ name = "stream_test",
srcs = [
- "buffered_stream_test.cc",
+ "stream_test.cc",
],
deps = [
":pw_stream",
diff --git a/pw_stream/BUILD.gn b/pw_stream/BUILD.gn
index a8efd15..cb7d6cf 100644
--- a/pw_stream/BUILD.gn
+++ b/pw_stream/BUILD.gn
@@ -63,10 +63,18 @@
}
pw_test_group("tests") {
- tests = [ ":memory_stream_test" ]
+ tests = [
+ ":memory_stream_test",
+ ":stream_test",
+ ]
}
pw_test("memory_stream_test") {
sources = [ "memory_stream_test.cc" ]
deps = [ ":pw_stream" ]
}
+
+pw_test("stream_test") {
+ sources = [ "stream_test.cc" ]
+ deps = [ ":pw_stream" ]
+}
diff --git a/pw_stream/public/pw_stream/null_stream.h b/pw_stream/public/pw_stream/null_stream.h
index 70048dc..eda1209 100644
--- a/pw_stream/public/pw_stream/null_stream.h
+++ b/pw_stream/public/pw_stream/null_stream.h
@@ -25,15 +25,15 @@
// Stream writer which quietly drops all of the data, similar to /dev/null.
class NullWriter final : public Writer {
- public:
- size_t ConservativeWriteLimit() const override {
- // In theory this can sink as much as is addressable, however this way it is
- // compliant with pw::StatusWithSize.
- return StatusWithSize::max_size();
- }
-
private:
- Status DoWrite(ConstByteSpan data) override { return Status::Ok(); }
+ Status DoWrite(ConstByteSpan) final { return Status::Ok(); }
+};
+
+// Stream reader which never reads any bytes. Always returns OUT_OF_RANGE, which
+// indicates there is no more data to read.
+class NullReader final : public Reader {
+ private:
+ StatusWithSize DoRead(ByteSpan) final { return StatusWithSize::OutOfRange(); }
};
} // namespace pw::stream
diff --git a/pw_stream/public/pw_stream/socket_stream.h b/pw_stream/public/pw_stream/socket_stream.h
index ac8e9e0..b7079e6 100644
--- a/pw_stream/public/pw_stream/socket_stream.h
+++ b/pw_stream/public/pw_stream/socket_stream.h
@@ -38,14 +38,6 @@
// Listen to the port and return after a client is connected
Status Init(uint16_t port);
- size_t ConservativeWriteLimit() const override {
- return std::numeric_limits<size_t>::max();
- }
-
- size_t ConservativeReadLimit() const override {
- return std::numeric_limits<size_t>::max();
- }
-
private:
Status DoWrite(std::span<const std::byte> data) override;
diff --git a/pw_stream/public/pw_stream/stream.h b/pw_stream/public/pw_stream/stream.h
index e52bb7c..9bbb069 100644
--- a/pw_stream/public/pw_stream/stream.h
+++ b/pw_stream/public/pw_stream/stream.h
@@ -75,7 +75,12 @@
// other contexts write data this number can go up or down for some Writers.
// Returns zero if, in the current state, Write() would not return
// Status::Ok().
- virtual size_t ConservativeWriteLimit() const = 0;
+ //
+ // Returns std::numeric_limits<size_t>::max() if the implementation has no
+ // limits on write sizes.
+ virtual size_t ConservativeWriteLimit() const {
+ return std::numeric_limits<size_t>::max();
+ }
private:
virtual Status DoWrite(ConstByteSpan data) = 0;
@@ -128,7 +133,12 @@
// number can go up or down for some Readers.
// Returns zero if, in the current state, Read() would not return
// Status::Ok().
- virtual size_t ConservativeReadLimit() const = 0;
+ //
+ // Returns std::numeric_limits<size_t>::max() if the implementation imposes no
+ // limits on read sizes.
+ virtual size_t ConservativeReadLimit() const {
+ return std::numeric_limits<size_t>::max();
+ }
private:
virtual StatusWithSize DoRead(ByteSpan dest) = 0;
diff --git a/pw_stream/public/pw_stream/sys_io_stream.h b/pw_stream/public/pw_stream/sys_io_stream.h
index e4c79ce..446f5a4 100644
--- a/pw_stream/public/pw_stream/sys_io_stream.h
+++ b/pw_stream/public/pw_stream/sys_io_stream.h
@@ -24,11 +24,6 @@
namespace pw::stream {
class SysIoWriter : public Writer {
- public:
- size_t ConservativeWriteLimit() const override {
- return std::numeric_limits<size_t>::max();
- }
-
private:
Status DoWrite(std::span<const std::byte> data) override {
return pw::sys_io::WriteBytes(data).status();
@@ -36,11 +31,6 @@
};
class SysIoReader : public Reader {
- public:
- size_t ConservativeReadLimit() const override {
- return std::numeric_limits<size_t>::max();
- }
-
private:
StatusWithSize DoRead(ByteSpan dest) override {
return pw::sys_io::ReadBytes(dest);
diff --git a/pw_stream/stream_test.cc b/pw_stream/stream_test.cc
new file mode 100644
index 0000000..fad335a
--- /dev/null
+++ b/pw_stream/stream_test.cc
@@ -0,0 +1,37 @@
+// Copyright 2020 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include "pw_stream/stream.h"
+
+#include <limits>
+
+#include "gtest/gtest.h"
+#include "pw_stream/null_stream.h"
+
+namespace pw::stream {
+namespace {
+
+TEST(Stream, DefaultConservativeWriteLimit) {
+ NullWriter stream;
+ EXPECT_EQ(stream.ConservativeWriteLimit(),
+ std::numeric_limits<size_t>::max());
+}
+
+TEST(Stream, DefaultConservativeReadLimit) {
+ NullReader stream;
+ EXPECT_EQ(stream.ConservativeReadLimit(), std::numeric_limits<size_t>::max());
+}
+
+} // namespace
+} // namespace pw::stream
