LibIPC: Add a simple IPC::Dictionary type (String key -> String value)

DevTools/IPCCompiler/main.cpp

@@ -230,6 +230,7 @@ int main(int argc, char** argv)
     out() << "#include <LibGfx/Rect.h>";
     out() << "#include <LibGfx/ShareableBitmap.h>";
     out() << "#include <LibIPC/Decoder.h>";
+    out() << "#include <LibIPC/Dictionary.h>";
     out() << "#include <LibIPC/Encoder.h>";
     out() << "#include <LibIPC/Endpoint.h>";
     out() << "#include <LibIPC/Message.h>";

Libraries/LibIPC/Decoder.cpp

@@ -26,6 +26,7 @@
 
 #include <AK/BufferStream.h>
 #include <LibIPC/Decoder.h>
+#include <LibIPC/Dictionary.h>
 
 namespace IPC {
 
@@ -112,4 +113,27 @@ bool Decoder::decode(String& value)
     return !m_stream.handle_read_failure();
 }
 
+bool Decoder::decode(Dictionary& dictionary)
+{
+    u64 size = 0;
+    m_stream >> size;
+    if (m_stream.handle_read_failure())
+        return false;
+    if (size >= NumericLimits<i32>::max()) {
+        ASSERT_NOT_REACHED();
+    }
+
+    for (size_t i = 0; i < size; ++i) {
+        String key;
+        if (!decode(key))
+            return false;
+        String value;
+        if (!decode(value))
+            return false;
+        dictionary.add(move(key), move(value));
+    }
+
+    return true;
+}
+
 }

Libraries/LibIPC/Decoder.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/Forward.h>
+#include <LibIPC/Forward.h>
 #include <LibIPC/Message.h>
 
 namespace IPC {
@@ -55,6 +56,7 @@ public:
     bool decode(i64&);
     bool decode(float&);
     bool decode(String&);
+    bool decode(Dictionary&);
 
     template<typename T>
     bool decode(T& value)

Libraries/LibIPC/Dictionary.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/HashMap.h>
+#include <AK/String.h>
+
+namespace IPC {
+
+class Dictionary {
+public:
+    Dictionary() {}
+
+    bool is_empty() const { return m_entries.is_empty(); }
+    size_t size() const { return m_entries.size(); }
+
+    void add(String key, String value)
+    {
+        m_entries.set(move(key), move(value));
+    }
+
+    template<typename Callback>
+    void for_each_entry(Callback callback) const
+    {
+        for (auto& it : m_entries) {
+            callback(it.key, it.value);
+        }
+    }
+
+    const HashMap<String, String>& entries() const { return m_entries; }
+
+private:
+    HashMap<String, String> m_entries;
+};
+
+}

Libraries/LibIPC/Encoder.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/String.h>
+#include <LibIPC/Dictionary.h>
 #include <LibIPC/Encoder.h>
 
 namespace IPC {
@@ -139,4 +140,13 @@ Encoder& Encoder::operator<<(const String& value)
     return *this << value.view();
 }
 
+Encoder& Encoder::operator<<(const Dictionary& dictionary)
+{
+    *this << (u64)dictionary.size();
+    dictionary.for_each_entry([this](auto& key, auto& value) {
+        *this << key << value;
+    });
+    return *this;
+}
+
 }

Libraries/LibIPC/Encoder.h

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <LibIPC/Forward.h>
 #include <LibIPC/Message.h>
 
 namespace IPC {
@@ -50,6 +51,7 @@ public:
     Encoder& operator<<(const char*);
     Encoder& operator<<(const StringView&);
     Encoder& operator<<(const String&);
+    Encoder& operator<<(const Dictionary&);
 
 private:
     MessageBuffer& m_buffer;

Libraries/LibIPC/Forward.h

@@ -29,6 +29,7 @@
 namespace IPC {
 
 class Decoder;
+class Dictionary;
 class Encoder;
 class Message;
 

Libraries/LibIPC/Makefile

@@ -1,5 +1,6 @@
 OBJS = \
     Decoder.o \
+    Dictionary.o \
     Encoder.o \
     Endpoint.o \
     Message.o