An FNMatch helper for upcoming functionality.

PiperOrigin-RevId: 556898736
Change-Id: Ic310bab090d6a92036034058520ed6641be86fbc

6 files changed, 203 insertions, 0 deletions

diff --git a/CMake/AbseilDll.cmake b/CMake/AbseilDll.cmake
index f0d984ae..a5a512bd 100644
--- a/CMake/AbseilDll.cmake
+++ b/CMake/AbseilDll.cmake
@@ -163,6 +163,8 @@ set(ABSL_INTERNAL_DLL_FILES
   "log/internal/conditions.cc"
   "log/internal/conditions.h"
   "log/internal/config.h"
+  "log/internal/fnmatch.h"
+  "log/internal/fnmatch.cc"
   "log/internal/globals.cc"
   "log/internal/globals.h"
   "log/internal/log_format.cc"
diff --git a/absl/log/CMakeLists.txt b/absl/log/CMakeLists.txt
index 2fc34d01..2c3307dc 100644
--- a/absl/log/CMakeLists.txt
+++ b/absl/log/CMakeLists.txt
@@ -671,6 +671,22 @@ absl_cc_library(
   PUBLIC
 )
 
+absl_cc_library(
+    NAME
+      log_internal_fnmatch
+    SRCS
+      "internal/fnmatch.cc"
+    HDRS
+      "internal/fnmatch.h"
+    COPTS
+      ${ABSL_DEFAULT_COPTS}
+    LINKOPTS
+      ${ABSL_DEFAULT_LINKOPTS}
+    DEPS
+      absl::config
+      absl::strings
+)
+
 # Test targets
 
 absl_cc_test(
@@ -1041,3 +1057,18 @@ absl_cc_test(
     GTest::gmock
     GTest::gtest_main
 )
+
+absl_cc_test(
+  NAME
+    internal_fnmatch_test
+  SRCS
+    "internal/fnmatch_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  LINKOPTS
+    ${ABSL_DEFAULT_LINKOPTS}
+  DEPS
+    absl::log_internal_fnmatch
+    GTest::gmock
+    GTest::gtest_main
+)
\ No newline at end of file
diff --git a/absl/log/internal/BUILD.bazel b/absl/log/internal/BUILD.bazel
index 555c5e5c..b8077a77 100644
--- a/absl/log/internal/BUILD.bazel
+++ b/absl/log/internal/BUILD.bazel
@@ -357,6 +357,18 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "fnmatch",
+    srcs = ["fnmatch.cc"],
+    hdrs = ["fnmatch.h"],
+    copts = ABSL_DEFAULT_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        "//absl/base:config",
+        "//absl/strings",
+    ],
+)
+
 # Test targets
 cc_test(
     name = "stderr_log_sink_test",
@@ -381,3 +393,14 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+cc_test(
+    name = "fnmatch_test",
+    srcs = ["fnmatch_test.cc"],
+    copts = ABSL_TEST_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        ":fnmatch",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
diff --git a/absl/log/internal/fnmatch.cc b/absl/log/internal/fnmatch.cc
new file mode 100644
index 00000000..be4e4b1c
--- /dev/null
+++ b/absl/log/internal/fnmatch.cc
@@ -0,0 +1,53 @@
+// Copyright 2023 The Abseil 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 "absl/log/internal/fnmatch.h"
+
+#include "absl/base/config.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace log_internal {
+bool FNMatch(absl::string_view pattern, absl::string_view str) {
+  while (true) {
+    if (pattern.empty()) {
+      // `pattern` is exhausted; succeed if all of `str` was consumed matching
+      // it.
+      return str.empty();
+    }
+    if (str.empty()) {
+      // `str` is exhausted; succeed if `pattern` is empty or all '*'s.
+      return pattern.find_first_not_of('*') == pattern.npos;
+    }
+    if (pattern.front() == '*') {
+      pattern.remove_prefix(1);
+      if (pattern.empty()) return true;
+      do {
+        if (FNMatch(pattern, str)) return true;
+        str.remove_prefix(1);
+      } while (!str.empty());
+      return false;
+    }
+    if (pattern.front() == '?' || pattern.front() == str.front()) {
+      pattern.remove_prefix(1);
+      str.remove_prefix(1);
+      continue;
+    }
+    return false;
+  }
+}
+}  // namespace log_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
diff --git a/absl/log/internal/fnmatch.h b/absl/log/internal/fnmatch.h
new file mode 100644
index 00000000..4ea147cc
--- /dev/null
+++ b/absl/log/internal/fnmatch.h
@@ -0,0 +1,35 @@
+// Copyright 2023 The Abseil 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.
+
+#ifndef ABSL_LOG_INTERNAL_FNMATCH_H_
+#define ABSL_LOG_INTERNAL_FNMATCH_H_
+
+#include "absl/base/config.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace log_internal {
+// Like POSIX `fnmatch`, but:
+// * accepts `string_view`
+// * does not allocate any dynamic memory
+// * only supports * and ? wildcards and not bracket expressions [...]
+// * wildcards may match /
+// * no backslash-escaping
+bool FNMatch(absl::string_view pattern, absl::string_view str);
+}  // namespace log_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_LOG_INTERNAL_FNMATCH_H_
diff --git a/absl/log/internal/fnmatch_test.cc b/absl/log/internal/fnmatch_test.cc
new file mode 100644
index 00000000..e16a64ec
--- /dev/null
+++ b/absl/log/internal/fnmatch_test.cc
@@ -0,0 +1,59 @@
+// Copyright 2023 The Abseil 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 "absl/log/internal/fnmatch.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace {
+using ::testing::IsFalse;
+using ::testing::IsTrue;
+
+TEST(FNMatchTest, Works) {
+  using absl::log_internal::FNMatch;
+  EXPECT_THAT(FNMatch("foo", "foo"), IsTrue());
+  EXPECT_THAT(FNMatch("foo", "bar"), IsFalse());
+  EXPECT_THAT(FNMatch("foo", "fo"), IsFalse());
+  EXPECT_THAT(FNMatch("foo", "foo2"), IsFalse());
+  EXPECT_THAT(FNMatch("bar/foo.ext", "bar/foo.ext"), IsTrue());
+  EXPECT_THAT(FNMatch("*ba*r/fo*o.ext*", "bar/foo.ext"), IsTrue());
+  EXPECT_THAT(FNMatch("bar/foo.ext", "bar/baz.ext"), IsFalse());
+  EXPECT_THAT(FNMatch("bar/foo.ext", "bar/foo"), IsFalse());
+  EXPECT_THAT(FNMatch("bar/foo.ext", "bar/foo.ext.zip"), IsFalse());
+  EXPECT_THAT(FNMatch("ba?/*.ext", "bar/foo.ext"), IsTrue());
+  EXPECT_THAT(FNMatch("ba?/*.ext", "baZ/FOO.ext"), IsTrue());
+  EXPECT_THAT(FNMatch("ba?/*.ext", "barr/foo.ext"), IsFalse());
+  EXPECT_THAT(FNMatch("ba?/*.ext", "bar/foo.ext2"), IsFalse());
+  EXPECT_THAT(FNMatch("ba?/*", "bar/foo.ext2"), IsTrue());
+  EXPECT_THAT(FNMatch("ba?/*", "bar/"), IsTrue());
+  EXPECT_THAT(FNMatch("ba?/?", "bar/"), IsFalse());
+  EXPECT_THAT(FNMatch("ba?/*", "bar"), IsFalse());
+  EXPECT_THAT(FNMatch("?x", "zx"), IsTrue());
+  EXPECT_THAT(FNMatch("*b", "aab"), IsTrue());
+  EXPECT_THAT(FNMatch("a*b", "aXb"), IsTrue());
+  EXPECT_THAT(FNMatch("", ""), IsTrue());
+  EXPECT_THAT(FNMatch("", "a"), IsFalse());
+  EXPECT_THAT(FNMatch("ab*", "ab"), IsTrue());
+  EXPECT_THAT(FNMatch("ab**", "ab"), IsTrue());
+  EXPECT_THAT(FNMatch("ab*?", "ab"), IsFalse());
+  EXPECT_THAT(FNMatch("*", "bbb"), IsTrue());
+  EXPECT_THAT(FNMatch("*", ""), IsTrue());
+  EXPECT_THAT(FNMatch("?", ""), IsFalse());
+  EXPECT_THAT(FNMatch("***", "**p"), IsTrue());
+  EXPECT_THAT(FNMatch("**", "*"), IsTrue());
+  EXPECT_THAT(FNMatch("*?", "*"), IsTrue());
+}
+
+}  // namespace