lib/pcre: migrate to PCRE2

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1352

NEWS

@@ -1,4 +1,5 @@
 ver 0.23.5 (not yet released)
+* migrate to PCRE2
 * GCC 12 build fixes
 
 ver 0.23.4 (2021/11/11)

src/db/plugins/meson.build

@@ -35,6 +35,7 @@ db_plugins = static_library(
   include_directories: inc,
   dependencies: [
     upnp_dep,
+    pcre_dep,
     libmpdclient_dep,
     log_dep,
   ],

src/lib/pcre/Error.cxx

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Error.hxx"
+
+#include <pcre2.h>
+
+namespace Pcre {
+
+ErrorCategory error_category;
+
+std::string
+ErrorCategory::message(int condition) const
+{
+	PCRE2_UCHAR8 buffer[256];
+	pcre2_get_error_message_8(condition, buffer, std::size(buffer));
+	return std::string{(const char *)buffer};
+}
+
+} // namespace Pcre

src/lib/pcre/Error.hxx

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <system_error>
+
+namespace Pcre {
+
+class ErrorCategory final : public std::error_category {
+public:
+	const char *name() const noexcept override {
+		return "pcre2";
+	}
+
+	std::string message(int condition) const override;
+};
+
+extern ErrorCategory error_category;
+
+inline std::system_error
+MakeError(int error, const char *msg) noexcept
+{
+	return std::system_error(error, error_category, msg);
+}
+
+} // namespace Pcre

src/lib/pcre/MatchData.hxx

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <pcre2.h>
+
+#include <cassert>
+#include <cstddef>
+#include <string_view>
+#include <utility>
+
+class MatchData {
+	friend class RegexPointer;
+
+	pcre2_match_data_8 *match_data = nullptr;
+	const char *s;
+	PCRE2_SIZE *ovector;
+	std::size_t n;
+
+	explicit MatchData(pcre2_match_data_8 *_md, const char *_s) noexcept
+		:match_data(_md), s(_s),
+		 ovector(pcre2_get_ovector_pointer_8(match_data))
+	{
+	}
+
+public:
+	MatchData() = default;
+
+	MatchData(MatchData &&src) noexcept
+		:match_data(std::exchange(src.match_data, nullptr)),
+		 s(src.s), ovector(src.ovector), n(src.n) {}
+
+	~MatchData() noexcept {
+		if (match_data != nullptr)
+			pcre2_match_data_free_8(match_data);
+	}
+
+	MatchData &operator=(MatchData &&src) noexcept {
+		using std::swap;
+		swap(match_data, src.match_data);
+		swap(s, src.s);
+		swap(ovector, src.ovector);
+		swap(n, src.n);
+		return *this;
+	}
+
+	constexpr operator bool() const noexcept {
+		return match_data != nullptr;
+	}
+
+	constexpr std::size_t size() const noexcept {
+		assert(*this);
+
+		return static_cast<std::size_t>(n);
+	}
+
+	[[gnu::pure]]
+	constexpr std::string_view operator[](std::size_t i) const noexcept {
+		assert(*this);
+		assert(i < size());
+
+		int start = ovector[2 * i];
+		if (start < 0)
+			return {};
+
+		int end = ovector[2 * i + 1];
+		assert(end >= start);
+
+		return { s + start, std::size_t(end - start) };
+	}
+
+	static constexpr std::size_t npos = ~std::size_t{};
+
+	[[gnu::pure]]
+	constexpr std::size_t GetCaptureStart(std::size_t i) const noexcept {
+		assert(*this);
+		assert(i < size());
+
+		int start = ovector[2 * i];
+		if (start < 0)
+			return npos;
+
+		return std::size_t(start);
+	}
+
+	[[gnu::pure]]
+	constexpr std::size_t GetCaptureEnd(std::size_t i) const noexcept {
+		assert(*this);
+		assert(i < size());
+
+		int end = ovector[2 * i + 1];
+		if (end < 0)
+			return npos;
+
+		return std::size_t(end);
+	}
+};

src/lib/pcre/RegexPointer.hxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2018 Content Management AG
+ * Copyright 2007-2021 CM4all GmbH
  * All rights reserved.
  *
  * author: Max Kellermann <mk@cm4all.com>
@@ -30,27 +30,17 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef REGEX_POINTER_HXX
+#pragma once
-#define REGEX_POINTER_HXX
 
-#include "util/StringView.hxx"
+#include "MatchData.hxx"
-#include "util/Compiler.h"
 
-#include <pcre.h>
+#include <pcre2.h>
 
-#include <array>
+#include <string_view>
-
-#if GCC_CHECK_VERSION(11,0)
-#pragma GCC diagnostic push
-/* bogus GCC 11 warning "ovector may be used uninitialized" in the
-   ovector.size() call */
-#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
-#endif
 
 class RegexPointer {
 protected:
-	pcre *re = nullptr;
+	pcre2_code_8 *re = nullptr;
-	pcre_extra *extra = nullptr;
 
 	unsigned n_capture = 0;
 
@@ -60,18 +50,28 @@ public:
 	}
 
 	[[gnu::pure]]
-	bool Match(StringView s) const noexcept {
+	MatchData Match(std::string_view s) const noexcept {
-		/* we don't need the data written to ovector, but PCRE can
+		MatchData match_data{
-		   omit internal allocations if we pass a buffer to
+			pcre2_match_data_create_from_pattern_8(re, nullptr),
-		   pcre_exec() */
+			s.data(),
-		std::array<int, 16> ovector;
+		};
-		return pcre_exec(re, extra, s.data, s.size,
+
-				 0, 0, &ovector.front(), ovector.size()) >= 0;
+		int n = pcre2_match_8(re, (PCRE2_SPTR8)s.data(), s.size(),
+				      0, 0,
+				      match_data.match_data, nullptr);
+		if (n < 0)
+			/* no match (or error) */
+			return {};
+
+		match_data.n = n;
+
+		if (n_capture >= match_data.n)
+			/* in its return value, PCRE omits mismatching
+			   optional captures if (and only if) they are
+			   the last capture; this kludge works around
+			   this */
+			match_data.n = n_capture + 1;
+
+		return match_data;
 	}
 };
-
-#if GCC_CHECK_VERSION(11,0)
-#pragma GCC diagnostic pop
-#endif
-
-#endif

src/lib/pcre/UniqueRegex.cxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2018 Content Management AG
+ * Copyright 2007-2021 CM4all GmbH
  * All rights reserved.
  *
  * author: Max Kellermann <mk@cm4all.com>
@@ -31,41 +31,40 @@
  */
 
 #include "UniqueRegex.hxx"
-#include "util/RuntimeError.hxx"
+#include "Error.hxx"
+
+#include <stdio.h>
 
 void
 UniqueRegex::Compile(const char *pattern, bool anchored, bool capture,
 		     bool caseless)
 {
-	constexpr int default_options = PCRE_DOTALL|PCRE_NO_AUTO_CAPTURE|PCRE_UTF8;
+	constexpr int default_options = PCRE2_DOTALL|PCRE2_NO_AUTO_CAPTURE;
 
-	int options = default_options;
+	uint32_t options = default_options;
 	if (anchored)
-		options |= PCRE_ANCHORED;
+		options |= PCRE2_ANCHORED;
 	if (capture)
-		options &= ~PCRE_NO_AUTO_CAPTURE;
+		options &= ~PCRE2_NO_AUTO_CAPTURE;
 	if (caseless)
-		options |= PCRE_CASELESS;
+		options |= PCRE2_CASELESS;
 
-	const char *error_string;
+	int error_number;
-	int error_offset;
+	PCRE2_SIZE error_offset;
-	re = pcre_compile(pattern, options, &error_string, &error_offset, nullptr);
+	re = pcre2_compile_8(PCRE2_SPTR8(pattern),
-	if (re == nullptr)
+			     PCRE2_ZERO_TERMINATED, options,
-		throw FormatRuntimeError("Error in regex at offset %d: %s",
+			     &error_number, &error_offset,
-					 error_offset, error_string);
+			     nullptr);
-
+	if (re == nullptr) {
-	int study_options = 0;
+		char msg[256];
-#ifdef PCRE_CONFIG_JIT
+		snprintf(msg, sizeof(msg), "Error in regex at offset %zu",
-	study_options |= PCRE_STUDY_JIT_COMPILE;
+			 error_offset);
-#endif
+		throw Pcre::MakeError(error_number, msg);
-	extra = pcre_study(re, study_options, &error_string);
-	if (extra == nullptr && error_string != nullptr) {
-		pcre_free(re);
-		re = nullptr;
-		throw FormatRuntimeError("Regex study error: %s", error_string);
 	}
 
-	int n;
+	pcre2_jit_compile_8(re, PCRE2_JIT_COMPLETE);
-	if (capture && pcre_fullinfo(re, extra, PCRE_INFO_CAPTURECOUNT, &n) == 0)
+
+	if (int n; capture &&
+	    pcre2_pattern_info_8(re, PCRE2_INFO_CAPTURECOUNT, &n) == 0)
 		n_capture = n;
 }

src/lib/pcre/UniqueRegex.hxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2018 Content Management AG
+ * Copyright 2007-2021 CM4all GmbH
  * All rights reserved.
  *
  * author: Max Kellermann <mk@cm4all.com>
@@ -30,15 +30,12 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef UNIQUE_REGEX_HXX
+#pragma once
-#define UNIQUE_REGEX_HXX
 
 #include "RegexPointer.hxx"
 
 #include <utility>
 
-#include <pcre.h>
-
 class UniqueRegex : public RegexPointer {
 public:
 	UniqueRegex() = default;
@@ -50,29 +47,22 @@ public:
 
 	UniqueRegex(UniqueRegex &&src) noexcept:RegexPointer(src) {
 		src.re = nullptr;
-		src.extra = nullptr;
 	}
 
 	~UniqueRegex() noexcept {
-		pcre_free(re);
+		if (re != nullptr)
-#ifdef PCRE_CONFIG_JIT
+			pcre2_code_free_8(re);
-		pcre_free_study(extra);
-#else
-		pcre_free(extra);
-#endif
 	}
 
-	UniqueRegex &operator=(UniqueRegex &&src) {
+	UniqueRegex &operator=(UniqueRegex &&src) noexcept {
 		using std::swap;
 		swap<RegexPointer>(*this, src);
 		return *this;
 	}
 
 	/**
-	 * Throws std::runtime_error on error.
+	 * Throws Pcre::Error on error.
 	 */
 	void Compile(const char *pattern, bool anchored, bool capture,
 		     bool caseless);
 };
-
-#endif

src/lib/pcre/meson.build

@@ -1,11 +1,17 @@
-pcre_dep = dependency('libpcre', required: get_option('pcre'))
+pcre_dep = dependency('libpcre2-8', required: get_option('pcre'))
 conf.set('HAVE_PCRE', pcre_dep.found())
 if not pcre_dep.found()
   subdir_done()
 endif
 
+pcre_dep = declare_dependency(
+  compile_args: '-DPCRE2_CODE_UNIT_WIDTH=0',
+  dependencies: pcre_dep,
+)
+
 pcre = static_library(
   'pcre',
+  'Error.cxx',
   'UniqueRegex.cxx',
   include_directories: inc,
   dependencies: [