AK: Add implicit String -> StringView conversion

And tidy up existing view() users.

AK/String.cpp

@@ -111,7 +111,7 @@ Vector<StringView> String::split_view(const char separator) const
     if (taillen != 0)
         v.append(substring_view(substart, taillen));
     if (characters()[length() - 1] == separator)
-        v.append(empty().view());
+        v.append(empty());
     return v;
 }
 

AK/StringView.cpp

@@ -3,6 +3,12 @@
 
 namespace AK {
 
+StringView::StringView(const AK::String& string)
+    : m_characters(string.characters())
+    , m_length(string.length())
+{
+}
+
 Vector<StringView> StringView::split_view(const char separator) const
 {
     if (is_empty())
@@ -23,7 +29,7 @@ Vector<StringView> StringView::split_view(const char separator) const
     if (taillen != 0)
         v.append(substring_view(substart, taillen));
     if (characters()[length() - 1] == separator)
-        v.append(String::empty().view());
+        v.append(String::empty());
     return v;
 }
 

AK/StringView.h

@@ -27,6 +27,7 @@ public:
                 ++m_length;
         }
     }
+    StringView(const AK::String& string);
 
     bool is_empty() const { return m_length == 0; }
     const char* characters() const { return m_characters; }

Kernel/Process.cpp

@@ -312,7 +312,7 @@ int Process::do_exec(String path, Vector<String> arguments, Vector<String> envir
     if (parts.is_empty())
         return -ENOENT;
 
-    auto result = VFS::the().open(path.view(), 0, 0, current_directory());
+    auto result = VFS::the().open(path, 0, 0, current_directory());
     if (result.is_error())
         return result.error();
     auto descriptor = result.value();

Servers/LookupServer/main.cpp

@@ -101,7 +101,7 @@ int main(int argc, char**argv)
         auto hostname = String(client_buffer, nrecv, Chomp);
         dbgprintf("LookupServer: Got request for '%s' (using IP %s)\n",
                   hostname.characters(),
-                  DNS_IP.view().characters());
+                  DNS_IP.characters());
 
         Vector<IPv4Address> addresses;
 
@@ -194,7 +194,7 @@ Vector<IPv4Address> lookup(const String& hostname, bool& did_timeout, const Stri
 
     dst_addr.sin_family = AF_INET;
     dst_addr.sin_port = htons(53);
-    rc = inet_pton(AF_INET, DNS_IP.view().characters(), &dst_addr.sin_addr);
+    rc = inet_pton(AF_INET, DNS_IP.characters(), &dst_addr.sin_addr);
 
     int nsent = sendto(fd, buffer.pointer(), buffer.size(), 0,(const struct sockaddr *)&dst_addr, sizeof(dst_addr));
     if (nsent < 0) {

Userland/sysctl.cpp

@@ -41,7 +41,7 @@ static void write_var(const String& name, const String& value)
         fprintf(stderr, "open: %s", f.error_string());
         exit(1);
     }
-    f.write(value.view());
+    f.write(value);
     if (f.error() < 0) {
         fprintf(stderr, "write: %s", f.error_string());
         exit(1);