Everywhere: Make ByteBuffer::{create_*,copy}() OOM-safe

AK/Base64.cpp

@@ -87,7 +87,8 @@ ByteBuffer decode_base64(const StringView& input)
             output.append(out2);
     }
 
-    return ByteBuffer::copy(output.data(), output.size());
+    // FIXME: Handle OOM failure.
+    return ByteBuffer::copy(output).release_value();
 }
 
 String encode_base64(ReadonlyBytes input)

AK/ByteBuffer.h

@@ -62,31 +62,35 @@ public:
         return *this;
     }
 
-    [[nodiscard]] static ByteBuffer create_uninitialized(size_t size)
+    [[nodiscard]] static Optional<ByteBuffer> create_uninitialized(size_t size)
     {
         auto buffer = ByteBuffer();
-        auto ok = buffer.try_resize(size);
-        VERIFY(ok);
-        return buffer;
+        if (!buffer.try_resize(size))
+            return {};
+        return { move(buffer) };
     }
 
-    [[nodiscard]] static ByteBuffer create_zeroed(size_t size)
+    [[nodiscard]] static Optional<ByteBuffer> create_zeroed(size_t size)
     {
-        auto buffer = create_uninitialized(size);
+        auto buffer_result = create_uninitialized(size);
+        if (!buffer_result.has_value())
+            return {};
+
+        auto& buffer = buffer_result.value();
         buffer.zero_fill();
         VERIFY(size == 0 || (buffer[0] == 0 && buffer[size - 1] == 0));
-        return buffer;
+        return buffer_result;
     }
 
-    [[nodiscard]] static ByteBuffer copy(void const* data, size_t size)
+    [[nodiscard]] static Optional<ByteBuffer> copy(void const* data, size_t size)
     {
         auto buffer = create_uninitialized(size);
-        if (size != 0)
-            __builtin_memcpy(buffer.data(), data, size);
+        if (buffer.has_value() && size != 0)
+            __builtin_memcpy(buffer->data(), data, size);
         return buffer;
     }
 
-    [[nodiscard]] static ByteBuffer copy(ReadonlyBytes bytes)
+    [[nodiscard]] static Optional<ByteBuffer> copy(ReadonlyBytes bytes)
     {
         return copy(bytes.data(), bytes.size());
     }
@@ -133,12 +137,13 @@ public:
     [[nodiscard]] void* end_pointer() { return data() + m_size; }
     [[nodiscard]] void const* end_pointer() const { return data() + m_size; }
 
+    // FIXME: Make this function handle failures too.
     [[nodiscard]] ByteBuffer slice(size_t offset, size_t size) const
     {
         // I cannot hand you a slice I don't have
         VERIFY(offset + size <= this->size());
 
-        return copy(offset_pointer(offset), size);
+        return copy(offset_pointer(offset), size).release_value();
     }
 
     void clear()
@@ -237,8 +242,10 @@ private:
         if (!other.m_inline) {
             m_outline_buffer = other.m_outline_buffer;
             m_outline_capacity = other.m_outline_capacity;
-        } else
+        } else {
+            VERIFY(other.m_size <= inline_capacity);
             __builtin_memcpy(m_inline_buffer, other.m_inline_buffer, other.m_size);
+        }
         other.m_size = 0;
         other.m_inline = true;
     }

AK/Hex.cpp

@@ -20,7 +20,11 @@ Optional<ByteBuffer> decode_hex(const StringView& input)
     if ((input.length() % 2) != 0)
         return {};
 
-    auto output = ByteBuffer::create_zeroed(input.length() / 2);
+    auto output_result = ByteBuffer::create_zeroed(input.length() / 2);
+    if (!output_result.has_value())
+        return {};
+
+    auto& output = output_result.value();
 
     for (size_t i = 0; i < input.length() / 2; ++i) {
         const auto c1 = decode_hex_digit(input[i * 2]);
@@ -34,7 +38,7 @@ Optional<ByteBuffer> decode_hex(const StringView& input)
         output[i] = (c1 << 4) + c2;
     }
 
-    return output;
+    return output_result;
 }
 
 String encode_hex(const ReadonlyBytes input)

AK/MemoryStream.h

@@ -224,7 +224,7 @@ public:
         size_t nwritten = 0;
         while (bytes.size() - nwritten > 0) {
             if ((m_write_offset + nwritten) % chunk_size == 0)
-                m_chunks.append(ByteBuffer::create_uninitialized(chunk_size));
+                m_chunks.append(ByteBuffer::create_uninitialized(chunk_size).release_value()); // FIXME: Handle possible OOM situation.
 
             nwritten += bytes.slice(nwritten).copy_trimmed_to(m_chunks.last().bytes().slice((m_write_offset + nwritten) % chunk_size));
         }
@@ -241,7 +241,8 @@ public:
 
     ByteBuffer copy_into_contiguous_buffer() const
     {
-        auto buffer = ByteBuffer::create_uninitialized(size());
+        // FIXME: Handle possible OOM situation.
+        auto buffer = ByteBuffer::create_uninitialized(size()).release_value();
 
         const auto nread = read_without_consuming(buffer);
         VERIFY(nread == buffer.size());

AK/String.cpp

@@ -176,7 +176,8 @@ ByteBuffer String::to_byte_buffer() const
 {
     if (!m_impl)
         return {};
-    return ByteBuffer::copy(reinterpret_cast<const u8*>(characters()), length());
+    // FIXME: Handle OOM failure.
+    return ByteBuffer::copy(bytes()).release_value();
 }
 
 template<typename T>

AK/StringBuilder.cpp

@@ -69,7 +69,8 @@ void StringBuilder::appendvf(char const* fmt, va_list ap)
 
 ByteBuffer StringBuilder::to_byte_buffer() const
 {
-    return ByteBuffer::copy(data(), length());
+    // FIXME: Handle OOM failure.
+    return ByteBuffer::copy(data(), length()).release_value();
 }
 
 String StringBuilder::to_string() const