Add tint::TmpFile

TmpFile constructs a temporary file that can be written to, and is automatically deleted on destruction.

Will be used to create a temporary source file for verifying generated HLSL and MSL against their shader compilers.

Change-Id: Ieaa6f257b93f4f2193dafe6297603816f6964928
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/41941
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

BUILD.gn

@@ -872,6 +872,8 @@ source_set("tint_unittests_core_src") {
     "src/type/u32_type_test.cc",
     "src/type/vector_type_test.cc",
     "src/type_determiner_test.cc",
+    "src/utils/tmpfile_test.cc",
+    "src/utils/tmpfile.h",
     "src/utils/unique_vector_test.cc",
     "src/validator/validator_builtins_test.cc",
     "src/validator/validator_control_block_test.cc",
@@ -882,6 +884,14 @@ source_set("tint_unittests_core_src") {
     "src/writer/float_to_string_test.cc",
   ]
 
+  if (is_linux || is_mac) {
+    sources += [ "src/utils/tmpfile_posix.cc" ]
+  } else if (is_win) {
+    sources += [ "src/utils/tmpfile_windows.cc" ]
+  } else {
+    sources += [ "src/utils/tmpfile_other.cc" ]
+  }
+
   configs += [
     ":tint_common_config",
     ":tint_unittests_config",

src/CMakeLists.txt

@@ -497,6 +497,8 @@ if(${TINT_BUILD_TESTS})
     type/type_manager_test.cc
     type/u32_type_test.cc
     type/vector_type_test.cc
+    utils/tmpfile_test.cc
+    utils/tmpfile.h
     utils/unique_vector_test.cc
     validator/validator_builtins_test.cc
     validator/validator_control_block_test.cc
@@ -508,6 +510,14 @@ if(${TINT_BUILD_TESTS})
     writer/float_to_string_test.cc
   )
 
+  if(UNIX OR APPLE)
+    list(APPEND TINT_TEST_SRCS utils/tmpfile_posix.cc)
+  elseif(WIN32)
+    list(APPEND TINT_TEST_SRCS utils/tmpfile_windows.cc)
+  else()
+    list(APPEND TINT_TEST_SRCS utils/tmpfile_other.cc)
+  endif()
+
   if(${TINT_BUILD_SPV_READER})
     list(APPEND TINT_TEST_SRCS
       reader/spirv/enum_converter_test.cc

src/utils/tmpfile.h

@@ -0,0 +1,74 @@
+// Copyright 2021 The Tint 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
+//
+//     http://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.
+
+#ifndef SRC_UTILS_TMPFILE_H_
+#define SRC_UTILS_TMPFILE_H_
+
+#include <sstream>
+#include <string>
+
+namespace tint {
+namespace utils {
+
+/// TmpFile constructs a temporary file that can be written to, and is
+/// automatically deleted on destruction.
+class TmpFile {
+ public:
+  /// Constructor.
+  /// Creates a new temporary file which can be written to.
+  /// The temporary file will be automatically deleted on destruction.
+  TmpFile();
+
+  /// Destructor.
+  /// Deletes the temporary file.
+  ~TmpFile();
+
+  /// @return true if the temporary file was successfully created.
+  operator bool() { return !path_.empty(); }
+
+  /// @return the path to the temporary file
+  std::string Path() const { return path_; }
+
+  /// Opens the temporary file and appends |size| bytes from |data| to the end
+  /// of the temporary file. The temporary file is closed again before
+  /// returning, allowing other processes to open the file on operating systems
+  /// that require exclusive ownership of opened files.
+  /// @param data the data to write to the end of the file
+  /// @param size the number of bytes to write from data
+  /// @returns true on success, otherwise false
+  bool Append(const void* data, size_t size) const;
+
+  /// Appends the argument to the end of the file.
+  /// @param data the data to write to the end of the file
+  /// @return a reference to this TmpFile
+  template <typename T>
+  inline TmpFile& operator<<(T&& data) {
+    std::stringstream ss;
+    ss << data;
+    std::string str = ss.str();
+    Append(str.data(), str.size());
+    return *this;
+  }
+
+ private:
+  TmpFile(const TmpFile&) = delete;
+  TmpFile& operator=(const TmpFile&) = delete;
+
+  std::string path_;
+};
+
+}  // namespace utils
+}  // namespace tint
+
+#endif  //  SRC_UTILS_TMPFILE_H_

src/utils/tmpfile_other.cc

@@ -0,0 +1,29 @@
+// Copyright 2021 The Tint 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
+//
+//     http://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 "src/utils/tmpfile.h"
+
+namespace tint {
+namespace utils {
+
+TmpFile::TmpFile() = default;
+
+TmpFile::~TmpFile() = default;
+
+bool TmpFile::Append(const void* data, size_t size) const {
+  return false;
+}
+
+}  // namespace utils
+}  // namespace tint

src/utils/tmpfile_posix.cc

@@ -0,0 +1,56 @@
+// Copyright 2021 The Tint 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
+//
+//     http://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 "src/utils/tmpfile.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <cstdio>
+
+namespace tint {
+namespace utils {
+
+namespace {
+
+std::string TmpFilePath() {
+  char name[] = "tint_XXXXXX";
+  int file = mkstemp(name);
+  if (file != -1) {
+    close(file);
+    return name;
+  }
+  return "";
+}
+
+}  // namespace
+
+TmpFile::TmpFile() : path_(TmpFilePath()) {}
+
+TmpFile::~TmpFile() {
+  if (!path_.empty()) {
+    remove(path_.c_str());
+  }
+}
+
+bool TmpFile::Append(const void* data, size_t size) const {
+  if (auto* file = fopen(path_.c_str(), "ab")) {
+    fwrite(data, size, 1, file);
+    fclose(file);
+    return true;
+  }
+  return false;
+}
+
+}  // namespace utils
+}  // namespace tint

src/utils/tmpfile_test.cc

@@ -0,0 +1,71 @@
+// Copyright 2021 The Tint 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
+//
+//     http://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 "src/utils/tmpfile.h"
+
+#include <fstream>
+
+#include "gtest/gtest.h"
+
+namespace tint {
+namespace utils {
+namespace {
+
+TEST(TmpFileTest, WriteReadAppendDelete) {
+  std::string path;
+  {
+    TmpFile tmp;
+    if (!tmp) {
+      GTEST_SKIP() << "Unable to create a temporary file";
+    }
+
+    path = tmp.Path();
+
+    // Write a string to the temporary file
+    tmp << "hello world\n";
+
+    // Check the content of the file
+    {
+      std::ifstream file(path);
+      ASSERT_TRUE(file);
+      std::string line;
+      EXPECT_TRUE(std::getline(file, line));
+      EXPECT_EQ(line, "hello world");
+      EXPECT_FALSE(std::getline(file, line));
+    }
+
+    // Write some more content to the file
+    tmp << 42;
+
+    // Check the content of the file again
+    {
+      std::ifstream file(path);
+      ASSERT_TRUE(file);
+      std::string line;
+      EXPECT_TRUE(std::getline(file, line));
+      EXPECT_EQ(line, "hello world");
+      EXPECT_TRUE(std::getline(file, line));
+      EXPECT_EQ(line, "42");
+      EXPECT_FALSE(std::getline(file, line));
+    }
+  }
+
+  // Check the file has been deleted when it fell out of scope
+  std::ifstream file(path);
+  ASSERT_FALSE(file);
+}
+
+}  // namespace
+}  // namespace utils
+}  // namespace tint

src/utils/tmpfile_windows.cc

@@ -0,0 +1,54 @@
+// Copyright 2021 The Tint 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
+//
+//     http://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 "src/utils/tmpfile.h"
+
+#include <stdio.h>
+#include <cstdio>
+
+namespace tint {
+namespace utils {
+
+namespace {
+
+std::string TmpFilePath() {
+  char name[L_tmpnam];
+  if (tmpnam_s(name, L_tmpnam - 1) == 0) {
+    return name;
+  }
+  return "";
+}
+
+}  // namespace
+
+TmpFile::TmpFile() : path_(TmpFilePath()) {}
+
+TmpFile::~TmpFile() {
+  if (!path_.empty()) {
+    remove(path_.c_str());
+  }
+}
+
+bool TmpFile::Append(const void* data, size_t size) const {
+  FILE* file = nullptr;
+  if (fopen_s(&file, path_.c_str(), "ab") != 0) {
+    return false;
+  }
+  fwrite(data, size, 1, file);
+  fclose(file);
+  return true;
+}
+
+}  // namespace utils
+}  // namespace tint