Perform Trim, TrimLeft & TrimRight transformations in-place

Author: eduar-hte

src/actions/transformations/trim.cc

@@ -15,36 +15,43 @@
 
 #include "trim.h"
 
+#include <algorithm>
+
 
 namespace modsecurity::actions::transformations {
 
 
-std::string *Trim::ltrim(std::string *s) {
-    s->erase(
-        s->begin(),
-        std::find_if(s->begin(), s->end(), [](unsigned char c) {
+bool Trim::ltrim(std::string &s) {
+    auto it = std::find_if(s.begin(), s.end(), [](unsigned char c) {
             return !std::isspace(c);
-        })
-    );
+        });
+
+    const bool changed = it != s.begin();
+
+    s.erase(s.begin(), it);
 
-    return s;
+    return changed;
 }
 
 
-std::string *Trim::rtrim(std::string *s) {
-    s->erase(
-        std::find_if(s->rbegin(), s->rend(), [](unsigned char c) {
+bool Trim::rtrim(std::string &s) {
+    auto it = std::find_if(s.rbegin(), s.rend(), [](unsigned char c) {
             return !std::isspace(c);
-        }).base(),
-        s->end()
-    );
+        }).base();
+
+    const bool changed = it != s.end();
 
-    return s;
+    s.erase(it, s.end());
+
+    return changed;
 }
 
 
-std::string *Trim::trim(std::string *s) {
-    return ltrim(rtrim(s));
+bool Trim::trim(std::string &s) {
+    bool changed = false;
+    changed |= rtrim(s);
+    changed |= ltrim(s);
+    return changed;
 }
 
 
@@ -55,11 +62,7 @@ Trim::Trim(const std::string &action)
 
 
 bool Trim::transform(std::string &value, const Transaction *trans) const {
-    std::string ret(value);
-    this->trim(&ret);
-    const auto changed = ret != value;
-    value = ret;
-    return changed;
+    return trim(value);
 }
 
 

src/actions/transformations/trim.h

@@ -26,9 +26,11 @@ class Trim : public Transformation {
 
     bool transform(std::string &value, const Transaction *trans) const override;
 
-    static std::string *ltrim(std::string *s);
-    static std::string *rtrim(std::string *s);
-    static std::string *trim(std::string *s);
+ protected:
+
+    static bool ltrim(std::string &s);
+    static bool rtrim(std::string &s);
+    static bool trim(std::string &s);
 };
 
 }  // namespace modsecurity::actions::transformations

src/actions/transformations/trim_left.cc

@@ -26,11 +26,7 @@ TrimLeft::TrimLeft(const std::string &action)
 }
 
 bool TrimLeft::transform(std::string &value, const Transaction *trans) const {
-    std::string ret(value);
-    this->ltrim(&ret);
-    const auto changed = ret != value;
-    value = ret;
-    return changed;
+    return ltrim(value);
 }
 
 

src/actions/transformations/trim_right.cc

@@ -25,11 +25,7 @@ TrimRight::TrimRight(const std::string &action)
 }
 
 bool TrimRight::transform(std::string &value, const Transaction *trans) const {
-    std::string ret(value);
-    this->rtrim(&ret);
-    const auto changed = ret != value;
-    value = ret;
-    return changed;
+    return rtrim(value);
 }