regex -> prefix

Signed-off-by: Alyssa Wilk <alyssar@chromium.org>

include/envoy/http/header_map.h

@@ -5,7 +5,6 @@
 #include <algorithm>
 #include <cstdint>
 #include <memory>
-#include <regex>
 #include <string>
 
 #include "envoy/common/pure.h"
@@ -467,12 +466,10 @@ class HeaderMap {
   virtual void remove(const LowerCaseString& key) PURE;
 
   /**
-   * Remove all instances of headers with key matching the supplied regex.
-   * @param key_matcher supplies the regex to match header keys against. Note
-   * that this will be matching against LowerCaseString, so should be using
-   * lowercase characters.
+   * Remove all instances of headers where the key begins with the supplied prefix.
+   * @param prefix supplies the prefix to match header keys against.
    */
-  virtual void remove(const std::regex& key_matcher) PURE;
+  virtual void removePrefix(const LowerCaseString& prefix) PURE;
 
   /**
    * @return the number of headers in the map.

source/common/http/header_map_impl.cc

@@ -9,6 +9,8 @@
 #include "common/common/utility.h"
 #include "common/singleton/const_singleton.h"
 
+#include "absl/strings/match.h"
+
 namespace Envoy {
 namespace Http {
 
@@ -464,14 +466,14 @@ void HeaderMapImpl::remove(const LowerCaseString& key) {
   }
 }
 
-void HeaderMapImpl::remove(const std::regex& regex) {
+void HeaderMapImpl::removePrefix(const LowerCaseString& prefix) {
   headers_.remove_if([&](const HeaderEntryImpl& entry) {
-    absl::string_view key = entry.key().getStringView();
-    bool to_remove = std::regex_search(key.begin(), key.end(), regex);
+    bool to_remove = absl::StartsWith(entry.key().getStringView(), prefix.get());
     if (to_remove) {
       // If this header should be removed, make sure any references in the
       // static lookup table are cleared as well.
-      StaticLookupEntry::EntryCb cb = ConstSingleton<StaticLookupTable>::get().find(key.data());
+      StaticLookupEntry::EntryCb cb =
+          ConstSingleton<StaticLookupTable>::get().find(entry.key().c_str());
       if (cb) {
         StaticLookupResponse ref_lookup_response = cb(*this);
         if (ref_lookup_response.entry_) {

source/common/http/header_map_impl.h

@@ -68,7 +68,7 @@ class HeaderMapImpl : public HeaderMap {
   void iterateReverse(ConstIterateCb cb, void* context) const override;
   Lookup lookup(const LowerCaseString& key, const HeaderEntry** entry) const override;
   void remove(const LowerCaseString& key) override;
-  void remove(const std::regex& regex) override;
+  void removePrefix(const LowerCaseString& key) override;
   size_t size() const override { return headers_.size(); }
 
 protected:

test/common/http/header_map_impl_test.cc

@@ -365,32 +365,24 @@ TEST(HeaderMapImplTest, RemoveRegex) {
   headers.addReference(key4, "value");
   headers.addReference(key5, "value");
 
-  // Trying to remove upper case strings from LowerCaseStrings will not work.
-  headers.remove(std::regex("^X-Prefix-"));
-  EXPECT_NE(nullptr, headers.get(key1));
-  EXPECT_NE(nullptr, headers.get(key2));
-  EXPECT_NE(nullptr, headers.get(key3));
-  EXPECT_NE(nullptr, headers.get(key4));
-  EXPECT_NE(nullptr, headers.get(key5));
-
   // Test removing the first header, middle headers, and the end header.
-  headers.remove(std::regex("^x-prefix-"));
+  headers.removePrefix(LowerCaseString("x-prefix-"));
   EXPECT_EQ(nullptr, headers.get(key1));
   EXPECT_NE(nullptr, headers.get(key2));
   EXPECT_EQ(nullptr, headers.get(key3));
   EXPECT_NE(nullptr, headers.get(key4));
   EXPECT_EQ(nullptr, headers.get(key5));
 
   // Remove all headers.
-  headers.remove(std::regex(".*"));
+  headers.removePrefix(LowerCaseString(""));
   EXPECT_EQ(nullptr, headers.get(key2));
   EXPECT_EQ(nullptr, headers.get(key4));
 
   // Add inline and remove by regex
   headers.insertContentLength().value(5);
   EXPECT_STREQ("5", headers.ContentLength()->value().c_str());
   EXPECT_EQ(1UL, headers.size());
-  headers.remove(std::regex("content"));
+  headers.removePrefix(LowerCaseString("content"));
   EXPECT_EQ(nullptr, headers.ContentLength());
 }