From 142e0990017a7f836ded172a253a2bfe5bb1311e Mon Sep 17 00:00:00 2001
From: Brian Gianforcaro <bgianf@serenityos.org>
Date: Sun, 9 Jan 2022 02:26:45 -0800
Subject: [PATCH] AK: Implement StringView::for_each_split_view

StringView::for_each_split_view allows you to process the splits in a
StringView without needing to allocate a Vector<StringView> to store
each of the parts.

Since we migrated the implementation from the normal split_view path, we
can also re-implement split_view in terms of for_each_split_view.
---
 AK/StringView.cpp | 21 ++-------------------
 AK/StringView.h   | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/AK/StringView.cpp b/AK/StringView.cpp
index a83e65e2296..4a569bbcb85 100644
--- a/AK/StringView.cpp
+++ b/AK/StringView.cpp
@@ -42,27 +42,10 @@ Vector<StringView> StringView::split_view(const char separator, bool keep_empty)
 
 Vector<StringView> StringView::split_view(StringView separator, bool keep_empty) const
 {
-    VERIFY(!separator.is_empty());
-
-    if (is_empty())
-        return {};
-
-    StringView view { *this };
-
     Vector<StringView> parts;
-
-    auto maybe_separator_index = find(separator);
-    while (maybe_separator_index.has_value()) {
-        auto separator_index = maybe_separator_index.value();
-        auto part_with_separator = view.substring_view(0, separator_index + separator.length());
-        if (keep_empty || separator_index > 0)
-            parts.append(part_with_separator.substring_view(0, separator_index));
-        view = view.substring_view_starting_after_substring(part_with_separator);
-        maybe_separator_index = view.find(separator);
-    }
-    if (keep_empty || !view.is_empty())
+    for_each_split_view(separator, keep_empty, [&](StringView view) {
         parts.append(view);
-
+    });
     return parts;
 }
 
diff --git a/AK/StringView.h b/AK/StringView.h
index 86f5747096e..a63f0590b52 100644
--- a/AK/StringView.h
+++ b/AK/StringView.h
@@ -120,6 +120,36 @@ public:
 
     [[nodiscard]] Vector<StringView> split_view_if(Function<bool(char)> const& predicate, bool keep_empty = false) const;
 
+    template<VoidFunction<StringView> Callback>
+    void for_each_split_view(char separator, bool keep_empty, Callback callback) const
+    {
+        StringView seperator_view { &separator, 1 };
+        for_each_split_view(seperator_view, keep_empty, callback);
+    }
+
+    template<VoidFunction<StringView> Callback>
+    void for_each_split_view(StringView separator, bool keep_empty, Callback callback) const
+    {
+        VERIFY(!separator.is_empty());
+
+        if (is_empty())
+            return;
+
+        StringView view { *this };
+
+        auto maybe_separator_index = find(separator);
+        while (maybe_separator_index.has_value()) {
+            auto separator_index = maybe_separator_index.value();
+            auto part_with_separator = view.substring_view(0, separator_index + separator.length());
+            if (keep_empty || separator_index > 0)
+                callback(part_with_separator.substring_view(0, separator_index));
+            view = view.substring_view_starting_after_substring(part_with_separator);
+            maybe_separator_index = view.find(separator);
+        }
+        if (keep_empty || !view.is_empty())
+            callback(view);
+    }
+
     // Create a Vector of StringViews split by line endings. As of CommonMark
     // 0.29, the spec defines a line ending as "a newline (U+000A), a carriage
     // return (U+000D) not followed by a newline, or a carriage return and a