AK: Introduce SourceGenerator::fork().

Previously, I abused the copy constructor, this is a lot better.

AK/SourceGenerator.h

@@ -34,54 +34,32 @@
 namespace AK {
 
 class SourceGenerator {
+    AK_MAKE_NONCOPYABLE(SourceGenerator);
+
 public:
     using MappingType = HashMap<StringView, String>;
 
-    explicit SourceGenerator(SourceGenerator& parent, char opening = '@', char closing = '@')
+    explicit SourceGenerator(StringBuilder& builder, char opening = '@', char closing = '@')
-        : m_parent(&parent)
+        : m_builder(builder)
         , m_opening(opening)
         , m_closing(closing)
     {
     }
-    explicit SourceGenerator(char opening = '@', char closing = '@')
+    explicit SourceGenerator(StringBuilder& builder, const MappingType& mapping, char opening = '@', char closing = '@')
-        : m_parent(nullptr)
+        : m_builder(builder)
+        , m_mapping(mapping)
         , m_opening(opening)
         , m_closing(closing)
     {
-        m_builder = new StringBuilder();
     }
 
+    SourceGenerator fork() { return SourceGenerator { m_builder, m_mapping, m_opening, m_closing }; }
+
     void set(StringView key, String value) { m_mapping.set(key, value); }
+    String get(StringView key) const { return m_mapping.get(key).value(); }
 
-    String lookup(StringView key) const
+    StringView as_string_view() const { return m_builder.string_view(); }
-    {
+    String as_string() const { return m_builder.build(); }
-        if (auto opt = m_mapping.get(key); opt.has_value())
-            return opt.value();
-
-        if (m_parent == nullptr) {
-            dbgln("Can't find key '{}'", key);
-            ASSERT_NOT_REACHED();
-        }
-
-        return m_parent->lookup(key);
-    }
-
-    String generate() const { return builder().build(); }
-
-    StringBuilder& builder()
-    {
-        if (m_parent)
-            return m_parent->builder();
-        else
-            return *m_builder;
-    }
-    const StringBuilder& builder() const
-    {
-        if (m_parent)
-            return m_parent->builder();
-        else
-            return *m_builder;
-    }
 
     void append(StringView pattern)
     {
@@ -94,7 +72,7 @@ public:
                 return lexer.consume_while([&](char ch) { return ch != stop; });
             };
 
-            builder().append(consume_until_without_consuming_stop_character(m_opening));
+            m_builder.append(consume_until_without_consuming_stop_character(m_opening));
 
             if (lexer.consume_specific(m_opening)) {
                 const auto placeholder = consume_until_without_consuming_stop_character(m_closing);
@@ -102,7 +80,7 @@ public:
                 if (!lexer.consume_specific(m_closing))
                     ASSERT_NOT_REACHED();
 
-                builder().append(lookup(placeholder));
+                m_builder.append(get(placeholder));
             } else {
                 ASSERT(lexer.is_eof());
             }
@@ -110,9 +88,8 @@ public:
     }
 
 private:
-    SourceGenerator* m_parent;
+    StringBuilder& m_builder;
     MappingType m_mapping;
-    OwnPtr<StringBuilder> m_builder;
     char m_opening, m_closing;
 };
 

AK/Tests/TestSourceGenerator.cpp

@@ -28,19 +28,31 @@
 
 #include <AK/SourceGenerator.h>
 
+TEST_CASE(wrap_builder)
+{
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+
+    generator.append("Hello, World!");
+
+    EXPECT_EQ(builder.string_view(), "Hello, World!");
+}
+
 TEST_CASE(generate_c_code)
 {
-    SourceGenerator generator;
+    StringBuilder builder;
+    SourceGenerator generator { builder };
     generator.set("name", "foo");
 
     generator.append("const char* @name@ (void) { return \"@name@\"; }");
 
-    EXPECT_EQ(generator.generate(), "const char* foo (void) { return \"foo\"; }");
+    EXPECT_EQ(generator.as_string_view(), "const char* foo (void) { return \"foo\"; }");
 }
 
 TEST_CASE(scoped)
 {
-    SourceGenerator global_generator;
+    StringBuilder builder;
+    SourceGenerator global_generator { builder };
 
     global_generator.append("\n");
 
@@ -49,8 +61,7 @@ TEST_CASE(scoped)
     global_generator.append("@foo@ @bar@\n"); // foo-0 bar-0
 
     {
-        SourceGenerator scoped_generator_1 { global_generator };
+        auto scoped_generator_1 = global_generator.fork();
-
         scoped_generator_1.set("bar", "bar-1");
         global_generator.append("@foo@ @bar@\n"); // foo-0 bar-0
     }
@@ -58,28 +69,25 @@ TEST_CASE(scoped)
     global_generator.append("@foo@ @bar@\n"); // foo-0 bar-0
 
     {
-        SourceGenerator scoped_generator_2 { global_generator };
+        auto scoped_generator_2 = global_generator.fork();
-
         scoped_generator_2.set("foo", "foo-2");
         scoped_generator_2.append("@foo@ @bar@\n"); // foo-2 bar-0
 
         {
-            // FIXME: This is never put onto the output?
+            auto scoped_generator_3 = scoped_generator_2.fork();
-
-            SourceGenerator scoped_generator_3 { scoped_generator_2 };
             scoped_generator_3.set("bar", "bar-3");
             scoped_generator_3.append("@foo@ @bar@\n"); // foo-2 bar-3
         }
 
         {
-            SourceGenerator scoped_generator_4 { global_generator };
+            auto scoped_generator_4 = global_generator.fork();
             scoped_generator_4.append("@foo@ @bar@\n"); // foo-0 bar-0
         }
 
         scoped_generator_2.append("@foo@ @bar@\n"); // foo-2 bar-0
     }
 
-    EXPECT_EQ(global_generator.generate(), "\nfoo-0 bar-0\nfoo-0 bar-0\nfoo-0 bar-0\nfoo-2 bar-0\nfoo-2 bar-3\nfoo-0 bar-0\nfoo-2 bar-0\n");
+    EXPECT_EQ(global_generator.as_string_view(), "\nfoo-0 bar-0\nfoo-0 bar-0\nfoo-0 bar-0\nfoo-2 bar-0\nfoo-2 bar-3\nfoo-0 bar-0\nfoo-2 bar-0\n");
 }
 
 TEST_MAIN(SourceGenerator)

DevTools/IPCCompiler/main.cpp

@@ -200,7 +200,8 @@ int main(int argc, char** argv)
     while (lexer.tell() < file_contents.size())
         parse_endpoint();
 
-    SourceGenerator generator;
+    StringBuilder builder;
+    SourceGenerator generator { builder };
 
     generator.append(R"~~~(
 #pragma once
@@ -219,7 +220,7 @@ int main(int argc, char** argv)
 )~~~");
 
     for (auto& endpoint : endpoints) {
-        SourceGenerator endpoint_generator { generator };
+        auto endpoint_generator = generator.fork();
 
         endpoint_generator.set("endpoint.name", endpoint.name);
         endpoint_generator.set("endpoint.magic", String::number(endpoint.magic));
@@ -234,7 +235,7 @@ namespace Messages::@endpoint.name@ {
 enum class MessageID : i32 {
 )~~~");
         for (auto& message : endpoint.messages) {
-            SourceGenerator message_generator { endpoint_generator };
+            auto message_generator = endpoint_generator.fork();
 
             message_ids.set(message.name, message_ids.size() + 1);
             message_generator.set("message.name", message.name);
@@ -292,8 +293,7 @@ enum class MessageID : i32 {
         };
 
         auto do_message = [&](const String& name, const Vector<Parameter>& parameters, const String& response_type = {}) {
-            SourceGenerator message_generator { endpoint_generator };
+            auto message_generator = endpoint_generator.fork();
-
             message_generator.set("message.name", name);
             message_generator.set("message.response_type", response_type);
             message_generator.set("message.constructor", constructor_for_message(name, parameters));
@@ -323,7 +323,7 @@ public:
 )~~~");
 
             for (auto& parameter : parameters) {
-                SourceGenerator parameter_generator { message_generator };
+                auto parameter_generator = message_generator.fork();
 
                 parameter_generator.set("parameter.type", parameter.type);
                 parameter_generator.set("parameter.name", parameter.name);
@@ -373,7 +373,7 @@ public:
 )~~~");
 
             for (auto& parameter : parameters) {
-                SourceGenerator parameter_generator { message_generator };
+                auto parameter_generator = message_generator.fork();
 
                 parameter_generator.set("parameter.name", parameter.name);
                 parameter_generator.append(R"~~~(
@@ -387,8 +387,7 @@ public:
 )~~~");
 
             for (auto& parameter : parameters) {
-                SourceGenerator parameter_generator { message_generator };
+                auto parameter_generator = message_generator.fork();
-
                 parameter_generator.set("parameter.type", parameter.type);
                 parameter_generator.set("parameter.name", parameter.name);
                 parameter_generator.append(R"~~~(
@@ -401,8 +400,7 @@ private:
             )~~~");
 
             for (auto& parameter : parameters) {
-                SourceGenerator parameter_generator { message_generator };
+                auto parameter_generator = message_generator.fork();
-
                 parameter_generator.set("parameter.type", parameter.type);
                 parameter_generator.set("parameter.name", parameter.name);
                 parameter_generator.append(R"~~~(
@@ -484,7 +482,7 @@ public:
 
         for (auto& message : endpoint.messages) {
             auto do_decode_message = [&](const String& name) {
-                SourceGenerator message_generator { endpoint_generator };
+                auto message_generator = endpoint_generator.fork();
 
                 message_generator.set("message.name", name);
 
@@ -532,7 +530,7 @@ public:
 )~~~");
         for (auto& message : endpoint.messages) {
             auto do_decode_message = [&](const String& name, bool returns_something) {
-                SourceGenerator message_generator { endpoint_generator };
+                auto message_generator = endpoint_generator.fork();
 
                 message_generator.set("message.name", name);
                 message_generator.append(R"~~~(
@@ -561,7 +559,7 @@ public:
 )~~~");
 
         for (auto& message : endpoint.messages) {
-            SourceGenerator message_generator { endpoint_generator };
+            auto message_generator = endpoint_generator.fork();
 
             message_generator.set("message.name", message.name);
 
@@ -589,7 +587,7 @@ private:
 )~~~");
     }
 
-    outln("{}", generator.generate());
+    outln("{}", generator.as_string_view());
 
 #ifdef DEBUG
     for (auto& endpoint : endpoints) {
@@ -612,6 +610,4 @@ private:
         }
     }
 #endif
-
-    return 0;
 }