Spreadsheet: Serialise Positions to URLs and add Sheet::from_uri()

Applications/Spreadsheet/Position.h

@@ -28,6 +28,7 @@
 
 #include <AK/String.h>
 #include <AK/Types.h>
+#include <AK/URL.h>
 
 namespace Spreadsheet {
 
@@ -44,6 +45,16 @@ struct Position {
     {
         return !(other == *this);
     }
+
+    URL to_url() const
+    {
+        URL url;
+        url.set_protocol("spreadsheet");
+        url.set_host("cell");
+        url.set_path(String::formatted("/{}", getpid()));
+        url.set_fragment(String::formatted("{}{}", column, row));
+        return url;
+    }
 };
 
 }

Applications/Spreadsheet/Spreadsheet.cpp

@@ -32,6 +32,7 @@
 #include <AK/JsonObject.h>
 #include <AK/JsonParser.h>
 #include <AK/TemporaryChange.h>
+#include <AK/URL.h>
 #include <LibCore/File.h>
 #include <LibJS/Parser.h>
 #include <LibJS/Runtime/Function.h>
@@ -202,6 +203,24 @@ Optional<Position> Sheet::parse_cell_name(const StringView& name)
     return Position { col, row.to_uint().value() };
 }
 
+Cell* Sheet::from_url(const URL& url)
+{
+    if (!url.is_valid()) {
+        dbgln("Invalid url: {}", url.to_string());
+        return nullptr;
+    }
+
+    if (url.protocol() != "spreadsheet" || url.host() != "cell") {
+        dbgln("Bad url: {}", url.to_string());
+        return nullptr;
+    }
+
+    // FIXME: Figure out a way to do this cross-process.
+    ASSERT(url.path() == String::formatted("/{}", getpid()));
+
+    return at(url.fragment());
+}
+
 RefPtr<Sheet> Sheet::from_json(const JsonObject& object, Workbook& workbook)
 {
     auto sheet = adopt(*new Sheet(workbook));

Applications/Spreadsheet/Spreadsheet.h

@@ -49,6 +49,9 @@ public:
 
     static Optional<Position> parse_cell_name(const StringView&);
 
+    Cell* from_url(const URL&);
+    const Cell* from_url(const URL& url) const { return const_cast<Sheet*>(this)->from_url(url); }
+
     JsonObject to_json() const;
     static RefPtr<Sheet> from_json(const JsonObject&, Workbook&);