Rewrite filesystem code (WIP)

This patch redoes the filesystem code from the FAT driver up to the
clipboard code in onplay.c.

Not every aspect of this is finished therefore it is still "WIP". I
don't wish to do too much at once (haha!). What is left to do is get
dircache back in the sim and find an implementation for the dircache
indicies in the tagcache and playlist code or do something else that
has the same benefit. Leaving these out for now does not make anything
unusable. All the basics are done.

Phone app code should probably get vetted (and app path handling
just plain rewritten as environment expansions); the SDL app and
Android run well.

Main things addressed:
1) Thread safety: There is none right now in the trunk code. Most of
what currently works is luck when multiple threads are involved or
multiple descriptors to the same file are open.

2) POSIX compliance: Many of the functions behave nothing like their
counterparts on a host system. This leads to inconsistent code or very
different behavior from native to hosted. One huge offender was
rename(). Going point by point would fill a book.

3) Actual running RAM usage: Many targets will use less RAM and less
stack space (some more RAM because I upped the number of cache buffers
for large memory). There's very little memory lying fallow in rarely-used
areas (see 'Key core changes' below). Also, all targets may open the same
number of directory streams whereas before those with less than 8MB RAM
were limited to 8, not 12 implying those targets will save slightly
less.

4) Performance: The test_disk plugin shows markedly improved performance,
particularly in the area of (uncached) directory scanning, due partly to
more optimal directory reading and to a better sector cache algorithm.
Uncached times tend to be better while there is a bit of a slowdown in
dircache due to it being a bit heavier of an implementation. It's not
noticeable by a human as far as I can say.

Key core changes:
1) Files and directories share core code and data structures.

2) The filesystem code knows which descriptors refer to same file.
This ensures that changes from one stream are appropriately reflected
in every open descriptor for that file (fileobj_mgr.c).

3) File and directory cache buffers are borrowed from the main sector
cache. This means that when they are not in use by a file, they are not
wasted, but used for the cache. Most of the time, only a few of them
are needed. It also means that adding more file and directory handles
is less expensive. All one must do in ensure a large enough cache to
borrow from.

4) Relative path components are supported and the namespace is unified.
It does not support full relative paths to an implied current directory;
what is does support is use of "." and "..". Adding the former would
not be very difficult. The namespace is unified in the sense that
volumes may be specified several times along with relative parts, e.g.:
"/<0>/foo/../../<1>/bar" :<=> "/<1>/bar".

5) Stack usage is down due to sharing of data, static allocation and
less duplication of strings on the stack. This requires more
serialization than I would like but since the number of threads is
limited to a low number, the tradoff in favor of the stack seems
reasonable.

6) Separates and heirarchicalizes (sic) the SIM and APP filesystem
code. SIM path and volume handling is just like the target. Some
aspects of the APP file code get more straightforward (e.g. no path
hashing is needed).

Dircache:
Deserves its own section. Dircache is new but pays homage to the old.
The old one was not compatible and so it, since it got redone, does
all the stuff it always should have done such as:

1) It may be update and used at any time during the build process.
No longer has one to wait for it to finish building to do basic file
management (create, remove, rename, etc.).

2) It does not need to be either fully scanned or completely disabled;
it can be incomplete (i.e. overfilled, missing paths), still be
of benefit and be correct.

3) Handles mounting and dismounting of individual volumes which means
a full rebuild is not needed just because you pop a new SD card in the
slot. Now, because it reuses its freed entry data, may rebuild only
that volume.

4) Much more fundamental to the file code. When it is built, it is
the keeper of the master file list whether enabled or not ("disabled"
is just a state of the cache). Its must always to ready to be started
and bind all streams opened prior to being enabled.

5) Maintains any short filenames in OEM format which means that it does
not need to be rebuilt when changing the default codepage.

Miscellaneous Compatibility:
1) Update any other code that would otherwise not work such as the
hotswap mounting code in various card drivers.

2) File management: Clipboard needed updating because of the behavioral
changes. Still needs a little more work on some finer points.

3) Remove now-obsolete functionality such as the mutex's "no preempt"
flag (which was only for the prior FAT driver).

4) struct dirinfo uses time_t rather than raw FAT directory entry
time fields. I plan to follow up on genericizing everything there
(i.e. no FAT attributes).

5) unicode.c needed some redoing so that the file code does not try
try to load codepages during a scan, which is actually a problem with
the current code. The default codepage, if any is required, is now
kept in RAM separarately (bufalloced) from codepages specified to
iso_decode() (which must not be bufalloced because the conversion
may be done by playback threads).

Brings with it some additional reusable core code:
1) Revised file functions: Reusable code that does things such as
safe path concatenation and parsing without buffer limitations or
data duplication. Variants that copy or alter the input path may be
based off these.

To do:
1) Put dircache functionality back in the sim. Treating it internally
as a different kind of file system seems the best approach at this
time.

2) Restore use of dircache indexes in the playlist and database or
something effectively the same. Since the cache doesn't have to be
complete in order to be used, not getting a hit on the cache doesn't
unambiguously say if the path exists or not.

Change-Id: Ia30f3082a136253e3a0eae0784e3091d138915c8
Reviewed-on: http://gerrit.rockbox.org/566
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested: Michael Sevakis <jethead71@rockbox.org>

1 files changed, 479 insertions, 0 deletions

diff --git a/firmware/target/hosted/filesystem-win32.c b/firmware/target/hosted/filesystem-win32.c
new file mode 100644
index 0000000000..19ef1c0aa7
--- /dev/null
+++ b/firmware/target/hosted/filesystem-win32.c
@@ -0,0 +1,479 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2014 by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#define RB_FILESYSTEM_OS
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include "config.h"
+#include "system.h"
+#include "file.h"
+#include "dir.h"
+#include "debug.h"
+#include "pathfuncs.h"
+#include "string-extra.h"
+
+#define SAME_FILE_INFO(lpInfo1, lpInfo2) \
+    ((lpInfo1)->dwVolumeSerialNumber == (lpInfo2)->dwVolumeSerialNumber && \
+     (lpInfo1)->nFileIndexHigh == (lpInfo2)->nFileIndexHigh &&             \
+     (lpInfo1)->nFileIndexLow == (lpInfo2)->nFileIndexLow)
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+static void win32_last_error_errno(void)
+{
+    switch (GetLastError())
+    {
+    case ERROR_FILE_NOT_FOUND:
+    case ERROR_PATH_NOT_FOUND:
+        errno = ENOENT;
+        break;
+    case ERROR_DIR_NOT_EMPTY:
+        errno = ENOTEMPTY;
+        break;
+    default:
+        errno = EIO;
+    }
+}
+
+#ifdef __MINGW32__
+#include <wchar.h>
+#include "rbunicode.h"
+
+static HANDLE win32_open(const char *ospath);
+static int win32_stat(const char *ospath, LPBY_HANDLE_FILE_INFORMATION lpInfo);
+
+unsigned short * strcpy_utf8ucs2(unsigned short *buffer,
+                                 const unsigned char *utf8)
+{
+    for (wchar_t *ucs2 = buffer;
+         ((utf8 = utf8decode(utf8, ucs2)), *ucs2); ucs2++);
+    return buffer;
+}
+
+#if 0
+unsigned char * strcpy_ucs2utf8(unsigned char *buffer,
+                                const unsigned short *ucs2)
+{
+    for (unsigned char *utf8 = buffer;
+         ((utf8 = utf8encode(*ucs2, utf8)), *ucs2); ucs2++);
+    return buffer;
+}
+
+size_t strlen_utf8ucs2(const unsigned char *utf8)
+{
+    /* This won't properly count multiword ucs2 so use the alternative
+       below for now which doesn't either */
+    size_t length = 0;
+    unsigned short ucschar[2];
+    for (unsigned char c = *utf8; c;
+         ((utf8 = utf8decode(utf8, ucschar)), c = *utf8))
+        length++;
+
+    return length;
+}
+#endif /* 0 */
+
+size_t strlen_utf8ucs2(const unsigned char *utf8)
+{
+    return utf8length(utf8);
+}
+
+size_t strlen_ucs2utf8(const unsigned short *ucs2)
+{
+    size_t length = 0;
+    unsigned char utf8char[4];
+
+    for (unsigned short c = *ucs2; c; (c = *++ucs2))
+        length += utf8encode(c, utf8char) - utf8char;
+
+    return length;
+}
+
+size_t strlcpy_ucs2utf8(char *buffer, const unsigned short *ucs2,
+                        size_t bufsize)
+{
+    if (!buffer)
+        bufsize = 0;
+
+    size_t length = 0;
+    unsigned char utf8char[4];
+
+    for (unsigned short c = *ucs2; c; (c = *++ucs2))
+    {
+        /* If the last character won't fit, this won't split it */
+        size_t utf8size = utf8encode(c, utf8char) - utf8char;
+        if ((length += utf8size) < bufsize)
+            buffer = mempcpy(buffer, utf8char, utf8size);
+    }
+
+    /* Above won't ever copy to very end */
+    if (bufsize)
+        *buffer = '\0';
+
+    return length;
+}
+
+#define _toucs2(utf8) \
+    ({ const char *_utf8 = (utf8);         \
+       size_t _l = strlen_utf8ucs2(_utf8); \
+       void *_buffer = alloca((_l + 1)*2); \
+       strcpy_utf8ucs2(_buffer, _utf8); })
+
+#define _toutf8(ucs2) \
+    ({ const char *_ucs2 = (ucs2);         \
+       size_t _l = strlen_ucs2utf8(_ucs2); \
+       void *_buffer = alloca(_l + 1);     \
+       strcpy_ucs2utf8(_buffer, _ucs2); })
+
+int os_open(const char *ospath, int oflag, ...)
+{
+    return _wopen(_toucs2(ospath), oflag __OPEN_MODE_ARG);
+}
+
+int os_creat(const char *ospath, mode_t mode)
+{
+    return _wcreat(_toucs2(ospath), mode);
+}
+
+int os_stat(const char *ospath, struct _stat *s)
+{
+    return _wstat(_toucs2(ospath), s);
+}
+
+int os_remove(const char *ospath)
+{
+    return _wremove(_toucs2(ospath));
+}
+
+int os_rename(const char *osold, const char *osnew)
+{
+    int errnum = errno;
+
+    const wchar_t *wchosold = _toucs2(osold);
+    const wchar_t *wchosnew = _toucs2(osnew);
+
+    int rc = _wrename(wchosold, wchosnew);
+    if (rc < 0 && errno == EEXIST)
+    {
+        /* That didn't work; do cheap POSIX mimic */
+        BY_HANDLE_FILE_INFORMATION info;
+        if (win32_stat(osold, &info))
+            return -1;
+
+        if ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) &&
+            !RemoveDirectoryW(wchosnew))
+        {
+            win32_last_error_errno();
+            return -1;
+        }
+
+        if (MoveFileExW(wchosold, wchosnew, MOVEFILE_REPLACE_EXISTING |
+                                            MOVEFILE_WRITE_THROUGH))
+        {
+            errno = errnum;
+            return 0;
+        }
+
+        errno = EIO;
+    }
+
+    return rc;
+}
+
+bool os_file_exists(const char *ospath)
+{
+    HANDLE h = win32_open(ospath);
+    if (h == INVALID_HANDLE_VALUE)
+        return false;
+
+    CloseHandle(h);
+    return true;
+}
+
+_WDIR * os_opendir(const char *osdirname)
+{
+    return _wopendir(_toucs2(osdirname));
+}
+
+int os_mkdir(const char *ospath, mode_t mode)
+{
+    return _wmkdir(_toucs2(ospath));
+    (void)mode;
+}
+
+int os_rmdir(const char *ospath)
+{
+    return _wrmdir(_toucs2(ospath));
+}
+
+int os_dirfd(_WDIR *osdirp)
+{
+#ifdef ENOTSUP
+    errno = ENOTSUP
+#else
+    errno = ENOSYS;
+#endif
+    return -1;
+    (void)osdirp;
+}
+
+int os_opendirfd(const char *osdirname)
+{
+    HANDLE h = win32_open(osdirname);
+    if (h == INVALID_HANDLE_VALUE)
+        return -1;
+
+    BY_HANDLE_FILE_INFORMATION info;
+    if (!GetFileInformationByHandle(h, &info))
+        errno = EIO;
+    else if (!(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
+        errno = ENOTDIR;
+    else
+    {
+        /* Convert OS handle to fd; the fd now owns it */
+        int osfd = _open_osfhandle((long)h, O_RDONLY);
+        if (osfd >= 0)
+            return osfd;
+    }
+
+    CloseHandle(h);
+    return -2;
+}
+#endif /* __MINGW32__ */
+
+static size_t win32_path_strip_root(const char *ospath)
+{
+    const char *p = ospath;
+    int c = toupper(*p);
+
+    if (c >= 'A' && c <= 'Z')
+    {
+        /* drive */
+        if ((c = *++p) == ':')
+            return 2;
+    }
+
+    if (c == '\\' && *++p == '\\')
+    {
+        /* UNC */
+        while ((c = *++p) && c != '/' && c != '\\');
+        return p - ospath;
+    }
+
+    return 0;
+}
+
+static HANDLE win32_open(const char *ospath)
+{
+    /* FILE_FLAG_BACKUP_SEMANTICS is required for this to succeed at opening
+       a directory */
+    HANDLE h = CreateFileW(_toucs2(ospath), GENERIC_READ,
+                           FILE_SHARE_READ | FILE_SHARE_WRITE |
+                           FILE_SHARE_DELETE, NULL, OPEN_EXISTING,
+                           FILE_FLAG_BACKUP_SEMANTICS, NULL);
+
+    if (h == INVALID_HANDLE_VALUE)
+        win32_last_error_errno();
+
+    return h;
+}
+
+static int win32_fstat(int osfd, HANDLE hFile,
+                       LPBY_HANDLE_FILE_INFORMATION lpInfo)
+{
+    /* The file descriptor takes precedence over the win32 file handle */
+    if (osfd >= 0)
+        hFile = (HANDLE)_get_osfhandle(osfd);
+
+    int rc = GetFileInformationByHandle(hFile, lpInfo) ? 0 : -1;
+    if (rc < 0)
+        win32_last_error_errno();
+
+    return rc;
+}
+
+static int win32_stat(const char *ospath, LPBY_HANDLE_FILE_INFORMATION lpInfo)
+{
+    HANDLE h = win32_open(ospath);
+    if (h == INVALID_HANDLE_VALUE)
+        return -1;
+
+    int rc = win32_fstat(-1, h, lpInfo);
+
+    CloseHandle(h);
+
+    return rc;
+}
+
+int os_opendir_and_fd(const char *osdirname, _WDIR **osdirpp,
+                      int *osfdp)
+{
+    /* another possible way is to use open() then fdopendir() */
+    *osdirpp = NULL;
+    *osfdp = -1;
+
+    _WDIR *dirp = os_opendir(osdirname);
+    if (!dirp)
+        return -1;
+
+    int rc = 0;
+    int errnum = errno;
+
+    int fd = os_dirfd(dirp);
+    if (fd < 0)
+    {
+        fd = os_opendirfd(osdirname);
+        rc = 1;
+    }
+
+    if (fd < 0)
+    {
+        os_closedir(dirp);
+        return -2;
+    }
+
+    errno = errnum;
+
+    *osdirpp = dirp;
+    *osfdp = fd;
+
+    return rc;
+}
+
+int os_fsamefile(int osfd1, int osfd2)
+{
+    BY_HANDLE_FILE_INFORMATION info1, info2;
+
+    if (!win32_fstat(osfd1, INVALID_HANDLE_VALUE, &info1) ||
+        !win32_fstat(osfd2, INVALID_HANDLE_VALUE, &info2))
+        return -1;
+
+    return SAME_FILE_INFO(&info1, &info2) ? 1 : 0;
+}
+
+int os_relate(const char *ospath1, const char *ospath2)
+{
+    DEBUGF("\"%s\" : \"%s\"\n", ospath1, ospath2);
+
+    if (!ospath2 || !*ospath2)
+    {
+        errno = ospath2 ? ENOENT : EFAULT;
+        return -1;
+    }
+
+    /* First file must stay open for duration so that its stats don't change */
+    HANDLE h1 = win32_open(ospath1);
+    if (h1 == INVALID_HANDLE_VALUE)
+        return -2;
+
+    BY_HANDLE_FILE_INFORMATION info1;
+    if (win32_fstat(-1, h1, &info1))
+    {
+        CloseHandle(h1);
+        return -3;
+    }
+
+    char path2buf[strlen(ospath2) + 1];
+    *path2buf = 0;
+
+    ssize_t len = 0;
+    const char *p = ospath2;
+    size_t rootlen = win32_path_strip_root(ospath2);
+    const char *sepmo = PA_SEP_SOFT;
+
+    if (rootlen)
+    {
+        strmemcpy(path2buf, ospath2, rootlen);
+        ospath2 += rootlen;
+        sepmo = PA_SEP_HARD;
+    }
+
+    int rc = RELATE_DIFFERENT;
+
+    while (1)
+    {
+        if (sepmo != PA_SEP_HARD &&
+            !(len = parse_path_component(&ospath2, &p)))
+        {
+            break;
+        }
+
+        char compname[len + 1];
+        strmemcpy(compname, p, len);
+
+        path_append(path2buf, sepmo, compname, sizeof (path2buf));
+        sepmo = PA_SEP_SOFT;
+
+        int errnum = errno; /* save and restore if not actually failing */
+        BY_HANDLE_FILE_INFORMATION info2;
+
+        if (!win32_stat(path2buf, &info2))
+        {
+            if (SAME_FILE_INFO(&info1, &info2))
+            {
+                rc = RELATE_SAME;
+            }
+            else if (rc == RELATE_SAME)
+            {
+                if (name_is_dot_dot(compname))
+                    rc = RELATE_DIFFERENT;
+                else if (!name_is_dot(compname))
+                    rc = RELATE_PREFIX;
+            }
+        }
+        else if (errno == ENOENT && !*GOBBLE_PATH_SEPCH(ospath2) &&
+                 !name_is_dot_dot(compname))
+        {
+            if (rc == RELATE_SAME)
+                rc = RELATE_PREFIX;
+
+            errno = errnum;
+            break;
+        }
+        else
+        {
+            rc = -4;
+            break;
+        }
+    }
+
+    CloseHandle(h1);
+
+    return rc;
+}
+
+void volume_size(IF_MV(int volume,) unsigned long *sizep, unsigned long *freep)
+{
+    ULARGE_INTEGER free = { .QuadPart = 0 },
+                   size = { .QuadPart = 0 };
+
+    char volpath[MAX_PATH];
+    if (os_volume_path(IF_MV(volume, ) volpath, sizeof (volpath)) >= 0)
+        GetDiskFreeSpaceExW(_toucs2(volpath), &free, &size, NULL);
+
+    if (sizep)
+        *sizep = size.QuadPart / 1024;
+
+    if (freep)
+        *freep = free.QuadPart / 1024;
+}