prefetch: use Regex instead of pcre (#12576)

Author: moonchen

plugins/prefetch/pattern.cc

@@ -23,6 +23,7 @@
  */
 
 #include "pattern.h"
+#include "tsutil/Regex.h"
 
 static void
 replaceString(String &str, const String &from, const String &to)
@@ -49,16 +50,13 @@ Pattern::Pattern() : _pattern(""), _replacement("") {}
 bool
 Pattern::init(const String &pattern, const String &replacement)
 {
-  pcreFree();
-
   _pattern.assign(pattern);
   _replacement.assign(replacement);
 
   _tokenCount = 0;
 
   if (!compile()) {
     PrefetchDebug("failed to initialize pattern:'%s', replacement:'%s'", pattern.c_str(), replacement.c_str());
-    pcreFree();
     return false;
   }
 
@@ -129,32 +127,7 @@ Pattern::init(const String &config)
 bool
 Pattern::empty() const
 {
-  return _pattern.empty() || nullptr == _re;
-}
-
-/**
- * @brief Frees PCRE library related resources.
- */
-void
-Pattern::pcreFree()
-{
-  if (_re) {
-    pcre_free(_re);
-    _re = nullptr;
-  }
-
-  if (_extra) {
-    pcre_free(_extra);
-    _extra = nullptr;
-  }
-}
-
-/**
- * @brief Destructor, frees PCRE related resources.
- */
-Pattern::~Pattern()
-{
-  pcreFree();
+  return _pattern.empty() || _regex.empty();
 }
 
 /**
@@ -204,16 +177,16 @@ Pattern::process(const String &subject, StringVector &result)
 bool
 Pattern::match(const String &subject)
 {
-  int matchCount;
   PrefetchDebug("matching '%s' to '%s'", _pattern.c_str(), subject.c_str());
 
-  if (!_re) {
+  if (_regex.empty()) {
     return false;
   }
 
-  matchCount = pcre_exec(_re, _extra, subject.c_str(), subject.length(), 0, PCRE_NOTEMPTY, nullptr, 0);
+  RegexMatches matches;
+  int          matchCount = _regex.exec(subject, matches, RE_NOTEMPTY);
   if (matchCount < 0) {
-    if (matchCount != PCRE_ERROR_NOMATCH) {
+    if (matchCount != RE_ERROR_NOMATCH) {
       PrefetchError("matching error %d", matchCount);
     }
     return false;
@@ -230,31 +203,26 @@ Pattern::match(const String &subject)
 bool
 Pattern::capture(const String &subject, StringVector &result)
 {
-  int matchCount;
-  int ovector[OVECOUNT];
-
   PrefetchDebug("matching '%s' to '%s'", _pattern.c_str(), subject.c_str());
 
-  if (!_re) {
+  if (_regex.empty()) {
     return false;
   }
 
-  matchCount = pcre_exec(_re, nullptr, subject.c_str(), subject.length(), 0, PCRE_NOTEMPTY, ovector, OVECOUNT);
-  if (matchCount < 0) {
-    if (matchCount != PCRE_ERROR_NOMATCH) {
+  RegexMatches matches;
+  int          matchCount = _regex.exec(subject, matches, RE_NOTEMPTY);
+
+  if (matchCount <= 0) {
+    if (matchCount != RE_ERROR_NOMATCH) {
       PrefetchError("matching error %d", matchCount);
     }
     return false;
   }
 
   for (int i = 0; i < matchCount; i++) {
-    int start  = ovector[2 * i];
-    int length = ovector[2 * i + 1] - ovector[2 * i];
-
-    String dst(subject, start, length);
-
-    PrefetchDebug("capturing '%s' %d[%d,%d]", dst.c_str(), i, ovector[2 * i], ovector[2 * i + 1]);
-    result.push_back(dst);
+    std::string_view match = matches[i];
+    result.emplace_back(match.data(), match.length());
+    PrefetchDebug("capturing '%s' %d", result.back().c_str(), i);
   }
 
   return true;
@@ -269,18 +237,17 @@ Pattern::capture(const String &subject, StringVector &result)
 bool
 Pattern::replace(const String &subject, String &result)
 {
-  int matchCount;
-  int ovector[OVECOUNT];
-
   PrefetchDebug("matching '%s' to '%s'", _pattern.c_str(), subject.c_str());
 
-  if (!_re) {
+  if (_regex.empty()) {
     return false;
   }
 
-  matchCount = pcre_exec(_re, nullptr, subject.c_str(), subject.length(), 0, PCRE_NOTEMPTY, ovector, OVECOUNT);
-  if (matchCount < 0) {
-    if (matchCount != PCRE_ERROR_NOMATCH) {
+  RegexMatches matches;
+  int          matchCount = _regex.exec(subject, matches, RE_NOTEMPTY);
+
+  if (matchCount <= 0) {
+    if (matchCount != RE_ERROR_NOMATCH) {
       PrefetchError("matching error %d", matchCount);
     }
     return false;
@@ -296,17 +263,15 @@ Pattern::replace(const String &subject, String &result)
 
   int previous = 0;
   for (int i = 0; i < _tokenCount; i++) {
-    int replIndex = _tokens[i];
-    int start     = ovector[2 * replIndex];
-    int length    = ovector[2 * replIndex + 1] - ovector[2 * replIndex];
+    int              replIndex = _tokens[i];
+    std::string_view dst       = matches[replIndex];
 
     String src(_replacement, _tokenOffset[i], 2);
-    String dst(subject, start, length);
 
-    PrefetchDebug("replacing '%s' with '%s'", src.c_str(), dst.c_str());
+    PrefetchDebug("replacing '%s' with '%.*s'", src.c_str(), static_cast<int>(dst.length()), dst.data());
 
     result.append(_replacement, previous, _tokenOffset[i] - previous);
-    result.append(dst);
+    result.append(dst.data(), dst.length());
 
     previous = _tokenOffset[i] + 2; /* 2 is the size of $0 or $1 or $2, ... or $9 */
   }
@@ -325,30 +290,12 @@ Pattern::replace(const String &subject, String &result)
 bool
 Pattern::compile()
 {
-  const char *errPtr;    /* PCRE error */
-  int         errOffset; /* PCRE error offset */
-
   PrefetchDebug("compiling pattern:'%s', replacement:'%s'", _pattern.c_str(), _replacement.c_str());
 
-  _re = pcre_compile(_pattern.c_str(), /* the pattern */
-                     0,                /* options */
-                     &errPtr,          /* for error message */
-                     &errOffset,       /* for error offset */
-                     nullptr);         /* use default character tables */
-
-  if (nullptr == _re) {
-    PrefetchError("compile of regex '%s' at char %d: %s", _pattern.c_str(), errOffset, errPtr);
-
-    return false;
-  }
-
-  _extra = pcre_study(_re, 0, &errPtr);
-
-  if ((nullptr == _extra) && (nullptr != errPtr) && (0 != *errPtr)) {
-    PrefetchError("failed to study regex '%s': %s", _pattern.c_str(), errPtr);
-
-    pcre_free(_re);
-    _re = nullptr;
+  std::string error;
+  int         erroffset;
+  if (!_regex.compile(_pattern, error, erroffset)) {
+    PrefetchError("compile of regex '%s' at char %d: %s", _pattern.c_str(), erroffset, error.c_str());
     return false;
   }
 
@@ -384,10 +331,6 @@ Pattern::compile()
     }
   }
 
-  if (!success) {
-    pcreFree();
-  }
-
   return success;
 }
 

plugins/prefetch/pattern.h

@@ -23,25 +23,18 @@
 
 #pragma once
 
-#ifdef HAVE_PCRE_PCRE_H
-#include <pcre/pcre.h>
-#else
-#include <pcre.h>
-#endif
-
 #include "common.h"
+#include "tsutil/Regex.h"
 
 /**
  * @brief PCRE matching, capturing and replacing
  */
 class Pattern
 {
 public:
-  static const int TOKENCOUNT = 10;             /**< @brief Capturing groups $0..$9 */
-  static const int OVECOUNT   = TOKENCOUNT * 3; /**< @brief pcre_exec() array count, handle 10 capture groups */
+  static const int TOKENCOUNT = 10; /**< @brief Capturing groups $0..$9 */
 
   Pattern();
-  virtual ~Pattern();
 
   bool init(const String &pattern, const String &replacement);
   bool init(const String &config);
@@ -54,10 +47,8 @@ class Pattern
 private:
   bool compile();
   bool failed(const String &subject) const;
-  void pcreFree();
 
-  pcre       *_re    = nullptr; /**< @brief PCRE compiled info structure, computed during initialization */
-  pcre_extra *_extra = nullptr; /**< @brief PCRE study data block, computed during initialization */
+  Regex _regex;
 
   String _pattern;     /**< @brief PCRE pattern string, containing PCRE patterns and capturing groups. */
   String _replacement; /**< @brief PCRE replacement string, containing $0..$9 to be replaced with content of the capturing groups */