From b40a6b3fa89a54805299d6c35133f3c975f58514 Mon Sep 17 00:00:00 2001
From: Yann MAGNIN <yann.magnin@protonmail.com>
Date: Tue, 1 Apr 2025 21:06:55 +0200
Subject: [PATCH] fs: prepare Fygue integration

---
 include/gint/fs.h    | 14 ++++++++++++++
 src/fs/close.c       | 11 +++++++++--
 src/fs/fdopendir.c   |  2 +-
 src/fs/fs.c          | 32 ++++++++++++++++++++++++++++++++
 src/fs/fugue/fugue.h |  1 -
 src/fs/fygue/fygue.h | 26 ++++++++++++++++++++++++++
 src/fs/lseek.c       | 12 ++++++++----
 src/fs/mkdir.c       |  4 +++-
 src/fs/open.c        | 21 +++++++++++++++++++--
 src/fs/read.c        | 11 +++++++----
 src/fs/rename.c      |  5 ++++-
 src/fs/rmdir.c       |  4 +++-
 src/fs/stat.c        |  8 +++++---
 src/fs/unlink.c      |  5 ++++-
 src/fs/write.c       | 13 ++++++++-----
 15 files changed, 143 insertions(+), 26 deletions(-)
 create mode 100644 src/fs/fygue/fygue.h

diff --git a/include/gint/fs.h b/include/gint/fs.h
index 6831dd2..b46d447 100644
--- a/include/gint/fs.h
+++ b/include/gint/fs.h
@@ -9,6 +9,7 @@
 extern "C" {
 #endif
 
+#include <gint/defs/types.h>
 #include <sys/types.h>
 #include <stddef.h>
 
@@ -100,6 +101,19 @@ char *fs_path_normalize(char const *path);
    calls to BFile. */
 uint16_t *fs_path_normalize_fc(char const *path);
 
+/* return True if the provided descriptor is a directory one */
+bool fs_descriptor_is_dir(fs_descriptor_t const *data);
+
+/* return True if the provided descriptor is a Fugue one */
+bool fs_descriptor_is_fugue(fs_descriptor_t const *data);
+
+/* return True if the provided descriptor is a Fygue one */
+bool fs_descriptor_is_fygue(fs_descriptor_t const *data);
+
+/* workaround to keep Fygue filesystem sync */
+//TODO: (re?)move me
+void fs_fygue_sync(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/fs/close.c b/src/fs/close.c
index 88c96bf..a67293c 100644
--- a/src/fs/close.c
+++ b/src/fs/close.c
@@ -11,9 +11,16 @@ int close(int fd)
 	}
 
 	int rc = 0;
-	if(d->type->close)
-		rc = d->type->close(d->data);
+	if(d->type->close == NULL)
+        goto end;
+    /* Fugue's close primitive can flush pending IO write operation. So, we
+     * are in the same situation than the write() primitive: force-sync
+     * Fygue's descriptor to ensure data intergrity */
+	rc = d->type->close(d->data);
+    if (fs_descriptor_is_fugue(d))
+        fs_fygue_sync();
 
+end:
 	fs_free_descriptor(fd);
 	return rc;
 }
diff --git a/src/fs/fdopendir.c b/src/fs/fdopendir.c
index 62e3547..c4360b2 100644
--- a/src/fs/fdopendir.c
+++ b/src/fs/fdopendir.c
@@ -11,7 +11,7 @@ DIR *fdopendir(int fd)
 		errno = EBADF;
 		return NULL;
 	}
-	if(desc->type != &fugue_dir_descriptor_type) {
+	if(!fs_descriptor_is_dir(desc)) {
 		errno = ENOTDIR;
 		return NULL;
 	}
diff --git a/src/fs/fs.c b/src/fs/fs.c
index 5bea0db..8b96d76 100644
--- a/src/fs/fs.c
+++ b/src/fs/fs.c
@@ -3,6 +3,8 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
+#include "fugue/fugue.h"
+#include "fygue/fygue.h"
 
 /* File descriptor table */
 static fs_descriptor_t *fdtable;
@@ -42,6 +44,36 @@ void fs_free_descriptor(int fd)
 	fdtable[fd].data = NULL;
 }
 
+//---
+// Utils
+//---
+
+bool fs_descriptor_is_fugue(fs_descriptor_t const *desc)
+{
+    return (
+        (desc->type == &fugue_dir_descriptor_type) ||
+        (desc->type == &fugue_descriptor_type)
+    );
+}
+
+bool fs_descriptor_is_fygue(fs_descriptor_t const *desc)
+{
+    return (
+        (desc->type == &fygue_dir_descriptor_type) ||
+        (desc->type == &fygue_descriptor_type)
+    );
+}
+
+void fs_fygue_sync(void)
+{
+    for (int i = 3 ; i < FS_FD_MAX ; i++) {
+        if (fdtable[i].type == NULL)
+            continue;
+        if (fs_descriptor_is_fygue(fdtable[i].data))
+            fygue_syncfs(fdtable[i].data);
+    }
+}
+
 int open_generic(fs_descriptor_type_t const *type, void *data, int fd)
 {
 	if(!fdtable) {
diff --git a/src/fs/fugue/fugue.h b/src/fs/fugue/fugue.h
index 54e659c..d9f32c3 100644
--- a/src/fs/fugue/fugue.h
+++ b/src/fs/fugue/fugue.h
@@ -31,7 +31,6 @@ int fugue_mkdir(char const *path, mode_t mode);
 
 int fugue_rmdir(char const *path);
 
-int fugue_stat(char const * restrict path, struct stat * restrict statbuf);
 
 /* Other functions */
 
diff --git a/src/fs/fygue/fygue.h b/src/fs/fygue/fygue.h
new file mode 100644
index 0000000..bda8de8
--- /dev/null
+++ b/src/fs/fygue/fygue.h
@@ -0,0 +1,26 @@
+#ifndef FS_FYGUE_H
+#define FS_FYGUE_H 1
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <gint/fs.h>
+
+/* File descriptor type */
+extern const fs_descriptor_type_t fygue_descriptor_type;
+/* Directory descriptor type */
+extern const fs_descriptor_type_t fygue_dir_descriptor_type;
+
+/* Specific implementations of some standard functions */
+
+extern int fygue_open(char const *path, int flags, mode_t mode);
+
+extern int fygue_stat(
+    char const * restrict path,
+    struct stat * restrict statbuf
+);
+
+extern int fygue_syncfs(void *desc);
+
+#endif /* FS_FYGUE_H */
diff --git a/src/fs/lseek.c b/src/fs/lseek.c
index c277c8b..efb94fc 100644
--- a/src/fs/lseek.c
+++ b/src/fs/lseek.c
@@ -15,9 +15,13 @@ off_t lseek(int fd, off_t offset, int whence)
 		return (ssize_t)-1;
 	}
 
-	if(d->type->lseek)
-		return d->type->lseek(d->data, offset, whence);
-
 	/* No seek function: cannot seek */
-	return 0;
+	if(d->type->lseek == NULL)
+        return 0;
+    /* BFile_Seek() can flush pending IO write operations. Sync Fygue's
+     * descriptor to avoid data corruption */
+    off_t off = d->type->lseek(d->data, offset, whence);
+    if (fs_descriptor_is_fugue(d))
+        fs_fygue_sync();
+    return off;
 }
diff --git a/src/fs/mkdir.c b/src/fs/mkdir.c
index 08940eb..88c6b18 100644
--- a/src/fs/mkdir.c
+++ b/src/fs/mkdir.c
@@ -4,5 +4,7 @@
 int mkdir(char const *path, mode_t mode)
 {
 	/* Standard mkdir() is the Fugue filesystem only */
-	return fugue_mkdir(path, mode);
+	int rc = fugue_mkdir(path, mode);
+    fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/open.c b/src/fs/open.c
index 03b82f9..9a2cbed 100644
--- a/src/fs/open.c
+++ b/src/fs/open.c
@@ -1,6 +1,7 @@
 #include <fcntl.h>
 #include <stdarg.h>
 #include "fugue/fugue.h"
+#include "fygue/fygue.h"
 
 int open(char const *path, int flags, ...)
 {
@@ -9,6 +10,22 @@ int open(char const *path, int flags, ...)
 	mode_t mode = va_arg(args, int);
 	va_end(args);
 
-	/* Standard open() is the Fugue filesystem only */
-	return fugue_open(path, flags, mode);
+	/* Standard open() use Fugue filesystem if a write operation
+     * is requested, otherwise use the Fygue filesystem */
+    int rc = 0;
+    if ((flags & O_WRONLY) || (flags & O_RDWR)) {
+        rc = fugue_open(path, flags, mode);
+    } else {
+        rc = fygue_open(path, flags, mode);
+    }
+    /* Even with Fygue open primitive, request a sync for all Fygue's
+     * descriptor because when some flags are set (e.g O_CREATE) Fygue
+     * invoke BFile_*() syscall that perform IO operation.
+     *
+     * Note that Fygue's open() primitive with perform a "lazy" open operation
+     * by simply ensure that the file exists and mark the file descriptor as
+     * dirty to force internal data refresh on the next Fygue's IO
+     * operation */
+    fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/read.c b/src/fs/read.c
index e214719..f75b608 100644
--- a/src/fs/read.c
+++ b/src/fs/read.c
@@ -10,9 +10,12 @@ ssize_t read(int fd, void *buf, size_t size)
 		return (ssize_t)-1;
 	}
 
-	if(d->type->read)
-		return d->type->read(d->data, buf, size);
-
 	/* No read function: we can't read anything */
-	return 0;
+	if(d->type->read == NULL)
+        return 0;
+    /* BFile_Read() can flush data in some circumstances, force-sync Fygue */
+    ssize_t rc = d->type->read(d->data, buf, size);
+    if (fs_descriptor_is_fugue(d))
+        fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/rename.c b/src/fs/rename.c
index 3c20b88..073f720 100644
--- a/src/fs/rename.c
+++ b/src/fs/rename.c
@@ -1,8 +1,11 @@
 #include <stdio.h>
+#include <gint/fs.h>
 #include "fugue/fugue.h"
 
 int rename(char const *oldpath, char const *newpath)
 {
 	/* Standard rename() is the Fugue filesystem only */
-	return fugue_rename(oldpath, newpath);
+	int rc = fugue_rename(oldpath, newpath);
+    fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/rmdir.c b/src/fs/rmdir.c
index ef2c9b7..b99e321 100644
--- a/src/fs/rmdir.c
+++ b/src/fs/rmdir.c
@@ -4,5 +4,7 @@
 int rmdir(char const *path)
 {
 	/* Standard rmdir() is the Fugue filesystem only */
-	return fugue_rmdir(path);
+	int rc = fugue_rmdir(path);
+    fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/stat.c b/src/fs/stat.c
index 872e6c1..eb9ad83 100644
--- a/src/fs/stat.c
+++ b/src/fs/stat.c
@@ -1,8 +1,10 @@
 #include <sys/stat.h>
-#include "fugue/fugue.h"
+#include "fygue/fygue.h"
 
 int stat(char const * restrict path, struct stat * restrict statbuf)
 {
-	/* Standard stat() is the Fugue filesystem only */
-	return fugue_stat(path, statbuf);
+	/* Standard stat() is also provided by Fugue, but rely on Casio's
+     * syscall which do not provide all of the information and request
+     * a world-switch (internally) to works */
+	return fygue_stat(path, statbuf);
 }
diff --git a/src/fs/unlink.c b/src/fs/unlink.c
index cb43104..9075fed 100644
--- a/src/fs/unlink.c
+++ b/src/fs/unlink.c
@@ -1,8 +1,11 @@
 #include <unistd.h>
+#include <gint/fs.h>
 #include "fugue/fugue.h"
 
 int unlink(char const *path)
 {
 	/* Standard unlink() is the Fugue filesystem only */
-	return fugue_unlink(path);
+	int rc = fugue_unlink(path);
+    fs_fygue_sync();
+    return rc;
 }
diff --git a/src/fs/write.c b/src/fs/write.c
index 8ce994c..0df7e69 100644
--- a/src/fs/write.c
+++ b/src/fs/write.c
@@ -9,10 +9,13 @@ ssize_t write(int fd, const void *buf, size_t size)
 		errno = EBADF;
 		return (ssize_t)-1;
 	}
-
-	if(d->type->write)
-		return d->type->write(d->data, buf, size);
-
 	/* No write function: discard the contents but show no error */
-	return size;
+	if(d->type->write == NULL)
+        return 0;
+    /* A special synchronisation must be performed to ensure that all
+     * Fygue's descriptor meta information are valid */
+    size = d->type->write(d->data, buf, size);
+    if (fs_descriptor_is_fugue(d))
+        fs_fygue_sync();
+    return size;
 }