string() Refactoring: creates an helper for REGEX REPLACE

1 files changed, 117 insertions, 0 deletions

diff --git a/Source/cmStringReplaceHelper.cxx b/Source/cmStringReplaceHelper.cxx
new file mode 100644
index 0000000..69b7ced
--- /dev/null
+++ b/Source/cmStringReplaceHelper.cxx
@@ -0,0 +1,117 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#include "cmStringReplaceHelper.h"
+
+#include "cmMakefile.h"
+#include <sstream>
+
+cmStringReplaceHelper::cmStringReplaceHelper(const std::string& regex,
+                                             const std::string& replace_expr,
+                                             cmMakefile* makefile)
+  : RegExString(regex)
+  , RegularExpression(regex)
+  , ReplaceExpression(replace_expr)
+  , Makefile(makefile)
+{
+  this->ParseReplaceExpression();
+}
+
+bool cmStringReplaceHelper::Replace(const std::string& input,
+                                    std::string& output)
+{
+  output.clear();
+
+  // Scan through the input for all matches.
+  std::string::size_type base = 0;
+  while (this->RegularExpression.find(input.c_str() + base)) {
+    if (this->Makefile != nullptr) {
+      this->Makefile->ClearMatches();
+      this->Makefile->StoreMatches(this->RegularExpression);
+    }
+    auto l2 = this->RegularExpression.start();
+    auto r = this->RegularExpression.end();
+
+    // Concatenate the part of the input that was not matched.
+    output += input.substr(base, l2);
+
+    // Make sure the match had some text.
+    if (r - l2 == 0) {
+      std::ostringstream error;
+      error << "regex \"" << this->RegExString << "\" matched an empty string";
+      this->ErrorString = error.str();
+      return false;
+    }
+
+    // Concatenate the replacement for the match.
+    for (const auto& replacement : this->Replacements) {
+      if (replacement.Number < 0) {
+        // This is just a plain-text part of the replacement.
+        output += replacement.Value;
+      } else {
+        // Replace with part of the match.
+        auto n = replacement.Number;
+        auto start = this->RegularExpression.start(n);
+        auto end = this->RegularExpression.end(n);
+        auto len = input.length() - base;
+        if ((start != std::string::npos) && (end != std::string::npos) &&
+            (start <= len) && (end <= len)) {
+          output += input.substr(base + start, end - start);
+        } else {
+          std::ostringstream error;
+          error << "replace expression \"" << this->ReplaceExpression
+                << "\" contains an out-of-range escape for regex \""
+                << this->RegExString << "\"";
+          this->ErrorString = error.str();
+          return false;
+        }
+      }
+    }
+
+    // Move past the match.
+    base += r;
+  }
+
+  // Concatenate the text after the last match.
+  output += input.substr(base, input.length() - base);
+
+  return true;
+}
+
+void cmStringReplaceHelper::ParseReplaceExpression()
+{
+  std::string::size_type l = 0;
+  while (l < this->ReplaceExpression.length()) {
+    auto r = this->ReplaceExpression.find('\\', l);
+    if (r == std::string::npos) {
+      r = this->ReplaceExpression.length();
+      this->Replacements.push_back(this->ReplaceExpression.substr(l, r - l));
+    } else {
+      if (r - l > 0) {
+        this->Replacements.push_back(this->ReplaceExpression.substr(l, r - l));
+      }
+      if (r == (this->ReplaceExpression.length() - 1)) {
+        this->ValidReplaceExpression = false;
+        this->ErrorString = "replace-expression ends in a backslash";
+        return;
+      }
+      if ((this->ReplaceExpression[r + 1] >= '0') &&
+          (this->ReplaceExpression[r + 1] <= '9')) {
+        this->Replacements.push_back(this->ReplaceExpression[r + 1] - '0');
+      } else if (this->ReplaceExpression[r + 1] == 'n') {
+        this->Replacements.push_back("\n");
+      } else if (this->ReplaceExpression[r + 1] == '\\') {
+        this->Replacements.push_back("\\");
+      } else {
+        this->ValidReplaceExpression = false;
+        std::ostringstream error;
+        error << "Unknown escape \"" << this->ReplaceExpression.substr(r, 2)
+              << "\" in replace-expression";
+        this->ErrorString = error.str();
+        return;
+      }
+      r += 2;
+    }
+    l = r;
+  }
+}