@trust is an encapsulation method, not an escape

[Zach the Mystic via Digitalmars-d]

On Saturday, 7 February 2015 at 01:43:01 UTC, Andrei Alexandrescu 
wrote:
> With the system proposal we're looking at something like:
>
> version (Posix) void[] read(in char[] name, size_t upTo = 
> size_t.max) @trusted
> {
>     import core.memory;
>     // A few internal configuration parameters {
>     enum size_t
>         minInitialAlloc = 1024 * 4,
>         maxInitialAlloc = size_t.max / 2,
>         sizeIncrement = 1024 * 16,
>         maxSlackMemoryAllowed = 1024;
>     // }
>
>     @system
>     {
>         immutable fd = 
> core.sys.posix.fcntl.open(name.tempCString(),
>             core.sys.posix.fcntl.O_RDONLY);
>     }
>     cenforce(fd != -1, name);
>     scope(exit) core.sys.posix.unistd.close(fd);
>
>     stat_t statbuf = void;
>     @system
>     {
>         cenforce(trustedFstat(fd, trustedRef(statbuf)) == 0, 
> name);
>     }
>
>     immutable initialAlloc = to!size_t(statbuf.st_size
>         ? min(statbuf.st_size + 1, maxInitialAlloc)
>         : minInitialAlloc);
>     void[] result = uninitializedArray!(ubyte[])(initialAlloc);
>     scope(failure) delete result;
>     size_t size = 0;
>
>     for (;;)
>     {
>         @system
>         {
>             immutable actual = core.sys.posix.unistd.read(fd, 
> result.ptr + size),
>                 min(result.length, upTo) - size);
>         }
>         cenforce(actual != -1, name);
>         if (actual == 0) break;
>         size += actual;
>         if (size < result.length) continue;
>         immutable newAlloc = size + sizeIncrement;
>         @system
>         {
>             result = GC.realloc(result.ptr, newAlloc, 
> GC.BlkAttr.NO_SCAN)[0 .. newAlloc];
>         }
>
>     @system
>     {
>         return result.length - size >= maxSlackMemoryAllowed
>             ? GC.realloc(result.ptr, size, 
> GC.BlkAttr.NO_SCAN)[0 .. size]
>             : result[0 .. size];
>     }
> }
>
> We want to move D forward, folks. This is not it.
>
>
> Andrei

Oh I see. There are three posts, in the latter two of which the 
little @trusted functions are already removed. I had thought they 
were all identical, but you obviously realized the little 
functions should be removed.