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, 114 insertions, 150 deletions

diff --git a/apps/plugin.c b/apps/plugin.c
index 8edc773239..8a6c577f69 100644
--- a/apps/plugin.c
+++ b/apps/plugin.c
@@ -18,6 +18,8 @@
  * KIND, either express or implied.
  *
  ****************************************************************************/
+#define DIRFUNCTIONS_DEFINED
+#define FILEFUNCTIONS_DEFINED
 #include "plugin.h"
 #include <ctype.h>
 #include <string.h>
@@ -40,8 +42,9 @@
 #include "pcmbuf.h"
 #include "errno.h"
 #include "diacritic.h"
-#include "filefuncs.h"
+#include "pathfuncs.h"
 #include "load_code.h"
+#include "file.h"
 
 #if CONFIG_CHARGING
 #include "power.h"
@@ -58,80 +61,119 @@
 #include "usbstack/usb_hid.h"
 #endif
 
-#if defined (SIMULATOR)
-#define PREFIX(_x_) sim_ ## _x_
-#elif defined (APPLICATION)
-#define PREFIX(_x_) app_ ## _x_
+#define WRAPPER(_x_) _x_ ## _wrapper
+
+#if (CONFIG_PLATFORM & PLATFORM_HOSTED)
+static unsigned char pluginbuf[PLUGIN_BUFFER_SIZE];
+void sim_lcd_ex_init(unsigned long (*getpixel)(int, int));
+void sim_lcd_ex_update_rect(int x, int y, int width, int height);
 #else
-#define PREFIX(_x_) _x_
+extern unsigned char pluginbuf[];
+#include "bitswap.h"
 #endif
 
-#if defined (APPLICATION)
-/* For symmetry reasons (we want app_ and sim_ to behave similarly), some
- * wrappers are needed */
-static int app_close(int fd)
+/* for actual plugins only, not for codecs */
+static int  plugin_size = 0;
+static bool (*pfn_tsr_exit)(bool reenter) = NULL; /* TSR exit callback */
+static char current_plugin[MAX_PATH];
+/* NULL if no plugin is loaded, otherwise the handle that lc_open() returned */
+static void *current_plugin_handle;
+
+char *plugin_get_current_filename(void);
+
+static void* plugin_get_audio_buffer(size_t *buffer_size);
+static void plugin_release_audio_buffer(void);
+static void plugin_tsr(bool (*exit_callback)(bool));
+
+
+#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
+/* File handle leak prophylaxis */
+#include "bitarray.h"
+#include "file_internal.h" /* for MAX_OPEN_FILES */
+
+#define PCOC_WRAPPER(_x_)   WRAPPER(_x_)
+
+BITARRAY_TYPE_DECLARE(plugin_check_open_close_bitmap_t, open_files_bitmap,
+                      MAX_OPEN_FILES)
+
+static plugin_check_open_close_bitmap_t open_files_bitmap;
+
+static void plugin_check_open_close__enter(void)
 {
-    return close(fd);
+    if (!current_plugin_handle)
+        open_files_bitmap_clear(&open_files_bitmap);
 }
 
-static ssize_t app_read(int fd, void *buf, size_t count)
+static void plugin_check_open_close__open(int fildes)
 {
-    return read(fd,buf,count);
+    if (fildes >= 0)
+        open_files_bitmap_set_bit(&open_files_bitmap, fildes);
 }
 
-static off_t app_lseek(int fd, off_t offset, int whence)
+static void plugin_check_open_close__close(int fildes)
 {
-    return lseek(fd,offset,whence);
+    if (fildes < 0)
+        return;
+
+    if (!open_files_bitmap_test_bit(&open_files_bitmap, fildes))
+    {
+        logf("double close from plugin");
+    }
+
+    open_files_bitmap_clear_bit(&open_files_bitmap, fildes);
 }
 
-static ssize_t app_write(int fd, const void *buf, size_t count)
+static int WRAPPER(open)(const char *path, int oflag, ...)
 {
-    return write(fd,buf,count);
+    int fildes = FS_PREFIX(open)(path, oflag __OPEN_MODE_ARG);
+    plugin_check_open_close__open(fildes);
+    return fildes;
 }
 
-static int app_ftruncate(int fd, off_t length)
+static int WRAPPER(creat)(const char *path, mode_t mode)
 {
-    return ftruncate(fd,length);
+    int fildes = FS_PREFIX(creat)(path __CREAT_MODE_ARG);
+    plugin_check_open_close__open(fildes);
+    return fildes;
+    (void)mode;
 }
-#endif
 
-#if defined(HAVE_PLUGIN_CHECK_OPEN_CLOSE) && (MAX_OPEN_FILES>32)
-#warning "MAX_OPEN_FILES>32, disabling plugin file open/close checking"
-#undef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-#endif
+static int WRAPPER(close)(int fildes)
+{
+    int rc = FS_PREFIX(close)(fildes);
+    if (rc >= 0)
+        plugin_check_open_close__close(fildes);
 
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-static unsigned int open_files;
-#endif
+    return rc;
+}
 
-#if (CONFIG_PLATFORM & PLATFORM_HOSTED)
-static unsigned char pluginbuf[PLUGIN_BUFFER_SIZE];
-void sim_lcd_ex_init(unsigned long (*getpixel)(int, int));
-void sim_lcd_ex_update_rect(int x, int y, int width, int height);
-#else
-extern unsigned char pluginbuf[];
-#include "bitswap.h"
-#endif
+static void plugin_check_open_close__exit(void)
+{
+    if (current_plugin_handle)
+        return;
 
-/* for actual plugins only, not for codecs */
-static int  plugin_size = 0;
-static bool (*pfn_tsr_exit)(bool reenter) = NULL; /* TSR exit callback */
-static char current_plugin[MAX_PATH];
-/* NULL if no plugin is loaded, otherwise the handle that lc_open() returned */
-static void *current_plugin_handle;
+    if (open_files_bitmap_is_clear(&open_files_bitmap))
+        return;
 
-char *plugin_get_current_filename(void);
+    logf("Plugin '%s' leaks file handles", plugin);
 
-/* Some wrappers used to monitor open and close and detect leaks*/
-static int open_wrapper(const char* pathname, int flags, ...);
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-static int close_wrapper(int fd);
-static int creat_wrapper(const char *pathname, mode_t mode);
-#endif
+    static const char *lines[] =
+        { ID2P(LANG_PLUGIN_ERROR), "#leak-file-handles" };
+    static const struct text_message message = { lines, 2 };
+    button_clear_queue(); /* Empty the keyboard buffer */
+    gui_syncyesno_run(&message, NULL, NULL);
 
-static void* plugin_get_audio_buffer(size_t *buffer_size);
-static void plugin_release_audio_buffer(void);
-static void plugin_tsr(bool (*exit_callback)(bool));
+    FOR_EACH_BITARRAY_SET_BIT(&open_files_bitmap, fildes)
+        WRAPPER(close)(fildes);
+}
+
+#else /* !HAVE_PLUGIN_CHECK_OPEN_CLOSE */
+
+#define PCOC_WRAPPER(_x_) FS_PREFIX(_x_)
+#define plugin_check_open_close__enter()
+#define plugin_check_open_close__exit()
+
+#endif /* HAVE_PLUGIN_CHECK_OPEN_CLOSE */
 
 static const struct plugin_api rockbox_api = {
 
@@ -339,24 +381,16 @@ static const struct plugin_api rockbox_api = {
 
     /* file */
     open_utf8,
-    (open_func)open_wrapper,
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-    close_wrapper,
-#else
-    PREFIX(close),
-#endif
-    (read_func)PREFIX(read),
-    PREFIX(lseek),
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-    (creat_func)creat_wrapper,
-#else
-    PREFIX(creat),
-#endif
-    (write_func)PREFIX(write),
-    PREFIX(remove),
-    PREFIX(rename),
-    PREFIX(ftruncate),
-    filesize,
+    PCOC_WRAPPER(open),
+    PCOC_WRAPPER(creat),
+    PCOC_WRAPPER(close),
+    FS_PREFIX(read),
+    FS_PREFIX(lseek),
+    FS_PREFIX(write),
+    FS_PREFIX(remove),
+    FS_PREFIX(rename),
+    FS_PREFIX(ftruncate),
+    FS_PREFIX(filesize),
     fdprintf,
     read_line,
     settings_parseline,
@@ -369,18 +403,18 @@ static const struct plugin_api rockbox_api = {
 #endif /* USING_STORAGE_CALLBACK */
     reload_directory,
     create_numbered_filename,
-    file_exists,
+    FS_PREFIX(file_exists),
     strip_extension,
     crc_32,
     filetype_get_attr,
 
     /* dir */
-    (opendir_func)opendir,
-    (closedir_func)closedir,
-    (readdir_func)readdir,
-    mkdir,
-    rmdir,
-    dir_exists,
+    FS_PREFIX(opendir),
+    FS_PREFIX(closedir),
+    FS_PREFIX(readdir),
+    FS_PREFIX(mkdir),
+    FS_PREFIX(rmdir),
+    FS_PREFIX(dir_exists),
     dir_get_info,
 
     /* browsing */
@@ -688,10 +722,11 @@ static const struct plugin_api rockbox_api = {
 #endif
     srand,
     rand,
-    (qsort_func)qsort,
+    (void *)qsort,
     kbd_input,
     get_time,
     set_time,
+    gmtime_r,
 #if CONFIG_RTC
     mktime,
 #endif
@@ -891,9 +926,7 @@ int plugin_load(const char* plugin, const void* parameter)
     /* allow voice to back off if the plugin needs lots of memory */
     talk_buffer_set_policy(TALK_BUFFER_LOOSE);
 
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-    open_files = 0;
-#endif
+    plugin_check_open_close__enter();
 
     int rc = p_hdr->entry_point(parameter);
     
@@ -947,24 +980,7 @@ int plugin_load(const char* plugin, const void* parameter)
     FOR_NB_SCREENS(i)
         viewportmanager_theme_undo(i, true);
 
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-    if(open_files != 0 && !current_plugin_handle)
-    {
-        int fd;
-        logf("Plugin '%s' leaks file handles", plugin);
-        
-        static const char *lines[] = 
-            { ID2P(LANG_PLUGIN_ERROR),
-              "#leak-file-handles" };
-        static const struct text_message message={ lines, 2 };
-        button_clear_queue(); /* Empty the keyboard buffer */
-        gui_syncyesno_run(&message, NULL, NULL);
-        
-        for(fd=0; fd < MAX_OPEN_FILES; fd++)
-            if(open_files & (1<<fd))
-                close_wrapper(fd);
-    }
-#endif
+    plugin_check_open_close__exit();
 
     if (rc == PLUGIN_ERROR)
         splash(HZ*2, str(LANG_PLUGIN_ERROR));
@@ -1027,55 +1043,3 @@ char *plugin_get_current_filename(void)
 {
     return current_plugin;
 }
-
-static int open_wrapper(const char* pathname, int flags, ...)
-{
-/* we don't have an 'open' function. it's a define. and we need
- * the real file_open, hence PREFIX() doesn't work here */
-    int fd;
-#if (CONFIG_PLATFORM & PLATFORM_HOSTED)
-    if (flags & O_CREAT)
-    {
-        va_list ap;
-        va_start(ap, flags);
-        fd = open(pathname, flags, va_arg(ap, unsigned int));
-        va_end(ap);
-    }
-    else
-        fd = open(pathname, flags);
-#else
-    fd = file_open(pathname,flags);
-#endif
-
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-    if(fd >= 0)
-        open_files |= 1<<fd;
-#endif
-    return fd;
-}
-
-#ifdef HAVE_PLUGIN_CHECK_OPEN_CLOSE
-static int close_wrapper(int fd)
-{
-    if((~open_files) & (1<<fd))
-    {
-        logf("double close from plugin");
-    }
-    if(fd >= 0)
-        open_files &= (~(1<<fd));
-
-    return PREFIX(close)(fd);
-}
-
-static int creat_wrapper(const char *pathname, mode_t mode)
-{
-    (void)mode;
-
-    int fd = PREFIX(creat)(pathname, mode);
-
-    if(fd >= 0)
-        open_files |= (1<<fd);
-
-    return fd;
-}
-#endif /* HAVE_PLUGIN_CHECK_OPEN_CLOSE */