http: add removeIf() header map function

include/envoy/http/header_map.h

@@ -547,6 +547,13 @@ class HeaderMap {
    */
   virtual size_t remove(const LowerCaseString& key) PURE;
 
+  /**
+   * Remove all instances of headers where the header matches the predicate.
+   * @param predicate supplies the predicate to match headers against.
+   * @return the number of headers removed.
+   */
+  virtual size_t removeIf(const std::function<bool(const HeaderEntry&)>& predicate) PURE;
+
   /**
    * Remove all instances of headers where the key begins with the supplied prefix.
    * @param prefix supplies the prefix to match header keys against.

source/common/http/header_map_impl.cc

@@ -483,28 +483,10 @@ void HeaderMapImpl::clear() {
   cached_byte_size_ = 0;
 }
 
-size_t HeaderMapImpl::remove(const LowerCaseString& key) {
+size_t HeaderMapImpl::removeIf(const std::function<bool(const HeaderEntry&)>& predicate) {
   const size_t old_size = headers_.size();
-  auto lookup = staticLookup(key.get());
-  if (lookup.has_value()) {
-    removeInline(lookup.value().entry_);
-  } else {
-    for (auto i = headers_.begin(); i != headers_.end();) {
-      if (i->key() == key.get().c_str()) {
-        subtractSize(i->key().size() + i->value().size());
-        i = headers_.erase(i);
-      } else {
-        ++i;
-      }
-    }
-  }
-  return old_size - headers_.size();
-}
-
-size_t HeaderMapImpl::removePrefix(const LowerCaseString& prefix) {
-  const size_t old_size = headers_.size();
-  headers_.remove_if([&prefix, this](const HeaderEntryImpl& entry) {
-    bool to_remove = absl::StartsWith(entry.key().getStringView(), prefix.get());
+  headers_.remove_if([&predicate, this](const HeaderEntryImpl& entry) {
+    const bool to_remove = predicate(entry);
     if (to_remove) {
       // If this header should be removed, make sure any references in the
       // static lookup table are cleared as well.
@@ -525,6 +507,18 @@ size_t HeaderMapImpl::removePrefix(const LowerCaseString& prefix) {
   return old_size - headers_.size();
 }
 
+size_t HeaderMapImpl::remove(const LowerCaseString& key) {
+  return HeaderMapImpl::removeIf([&key](const HeaderEntry& entry) -> bool {
+    return key.get() == entry.key().getStringView();
+  });
+}
+
+size_t HeaderMapImpl::removePrefix(const LowerCaseString& prefix) {
+  return HeaderMapImpl::removeIf([&prefix](const HeaderEntry& entry) -> bool {
+    return absl::StartsWith(entry.key().getStringView(), prefix.get());
+  });
+}
+
 void HeaderMapImpl::dumpState(std::ostream& os, int indent_level) const {
   iterate([&os,
            spaces = spacesForLevel(indent_level)](const HeaderEntry& header) -> HeaderMap::Iterate {

source/common/http/header_map_impl.h

@@ -90,6 +90,7 @@ class HeaderMapImpl : NonCopyable {
   void iterateReverse(HeaderMap::ConstIterateCb cb) const;
   void clear();
   size_t remove(const LowerCaseString& key);
+  size_t removeIf(const std::function<bool(const HeaderEntry&)>& predicate);
   size_t removePrefix(const LowerCaseString& key);
   size_t size() const { return headers_.size(); }
   bool empty() const { return headers_.empty(); }
@@ -304,6 +305,9 @@ template <class Interface> class TypedHeaderMapImpl : public HeaderMapImpl, publ
   }
   void clear() override { HeaderMapImpl::clear(); }
   size_t remove(const LowerCaseString& key) override { return HeaderMapImpl::remove(key); }
+  size_t removeIf(const std::function<bool(const HeaderEntry&)>& predicate) override {
+    return HeaderMapImpl::removeIf(predicate);
+  }
   size_t removePrefix(const LowerCaseString& key) override {
     return HeaderMapImpl::removePrefix(key);
   }

test/common/http/header_map_impl_test.cc

@@ -520,7 +520,28 @@ TEST(HeaderMapImplTest, Remove) {
   EXPECT_EQ(0UL, headers.remove(Headers::get().ContentLength));
 }
 
-TEST(HeaderMapImplTest, RemoveRegex) {
+TEST(HeaderMapImplTest, RemoveIf) {
+  LowerCaseString key1 = LowerCaseString("X-postfix-foo");
+  LowerCaseString key2 = LowerCaseString("X-postfix-");
+  LowerCaseString key3 = LowerCaseString("x-postfix-eep");
+
+  TestRequestHeaderMapImpl headers;
+  headers.addReference(key1, "value");
+  headers.addReference(key2, "value");
+  headers.addReference(key3, "value");
+
+  EXPECT_EQ(0UL, headers.removeIf([](const HeaderEntry&) -> bool { return false; }));
+
+  EXPECT_EQ(2UL, headers.removeIf([](const HeaderEntry& entry) -> bool {
+    return absl::EndsWith(entry.key().getStringView(), "foo") ||
+           absl::EndsWith(entry.key().getStringView(), "eep");
+  }));
+
+  TestRequestHeaderMapImpl expected{{"X-postfix-", "value"}};
+  EXPECT_EQ(expected, headers);
+}
+
+TEST(HeaderMapImplTest, RemovePrefix) {
   // These will match.
   LowerCaseString key1 = LowerCaseString("X-prefix-foo");
   LowerCaseString key3 = LowerCaseString("X-Prefix-");
@@ -552,7 +573,7 @@ TEST(HeaderMapImplTest, RemoveRegex) {
   EXPECT_EQ(nullptr, headers.get(key2));
   EXPECT_EQ(nullptr, headers.get(key4));
 
-  // Add inline and remove by regex
+  // Add inline and remove by prefix
   headers.setContentLength(5);
   EXPECT_EQ("5", headers.getContentLengthValue());
   EXPECT_EQ(1UL, headers.size());

test/test_common/utility.h

@@ -920,6 +920,11 @@ template <class Interface, class Impl> class TestHeaderMapImplBase : public Inte
     header_map_->verifyByteSizeInternalForTest();
     return headers_removed;
   }
+  size_t removeIf(const std::function<bool(const HeaderEntry&)>& predicate) override {
+    size_t headers_removed = header_map_->removeIf(predicate);
+    header_map_->verifyByteSizeInternalForTest();
+    return headers_removed;
+  }
   size_t removePrefix(const LowerCaseString& key) override {
     size_t headers_removed = header_map_->removePrefix(key);
     header_map_->verifyByteSizeInternalForTest();