libos: Add File::read_all() and File::read_all_as_string()

libos/include/os/File.h

@@ -34,8 +34,10 @@ namespace os
         Result<void> write(const Buffer& buf);
 
         Result<String> read_line();
+        Result<String> read_all_as_string();
 
         Result<void> read(Buffer& buf, usize size);
+        Result<Buffer> read_all();
 
         Result<int> getchar();
 

libos/src/File.cpp

@@ -131,6 +131,36 @@ namespace os
         return String::from_cstring(data.data());
     }
 
+    Result<String> File::read_all_as_string()
+    {
+        StringBuilder sb;
+
+        while (true)
+        {
+            auto line = TRY(read_line());
+            if (line.is_empty()) break;
+            TRY(sb.add(line));
+        }
+
+        return sb.string();
+    }
+
+    Result<Buffer> File::read_all()
+    {
+        Vector<u8> data;
+
+        while (true)
+        {
+            int c = TRY(getchar());
+            if (c == -1) break;
+            TRY(data.try_append((u8)c));
+        }
+
+        Buffer buf;
+        TRY(buf.append_data(data.data(), data.size()));
+        return buf;
+    }
+
     Result<void> File::read(Buffer& buf, usize size)
     {
         u8* slice = TRY(buf.slice(0, size));
@@ -144,9 +174,9 @@ namespace os
 
     Result<int> File::getchar()
     {
-        char value;
+        u8 value;
 
-        usize nread = TRY(raw_read((u8*)&value, 1));
+        usize nread = TRY(raw_read(&value, 1));
         if (!nread) return -1;
 
         return value;