procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Avoid caching file status when they are about to change

Browse source 
* java/org/gnu/emacs/EmacsSafThread.java (EmacsSafThread)
(cacheFileStatus): New argument NO_CACHE.
(cacheDirectoryFromCursor, statDocument1):
* java/org/gnu/emacs/EmacsService.java (EmacsService)
(statDocument): Plumb that argument through each of these wrapper
functions.
* src/android.c (android_init_emacs_service): Adjust JNI
function signatures to agree with statDocument1.
* src/androidvfs.c (android_saf_stat): Plumb that argument
through here.
(android_saf_tree_stat, android_saf_file_open): And don't cache
file status if a write is imminent.
This commit is contained in:
Po Lu 2023-08-08 16:17:10 +08:00
parent 27113c22f7
commit 440f017658
4 changed files with 41 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
java/org/gnu/emacs/EmacsSafThread.java
View file

@ -437,11 +437,14 @@ private static final class CacheEntry
/* Cache file status for DOCUMENTID within TOPLEVEL. Value is the
new cache entry. CURSOR is the cursor from where to retrieve the
file status, in the form of the columns COLUMN_FLAGS,
COLUMN_SIZE, COLUMN_MIME_TYPE and COLUMN_LAST_MODIFIED. */
COLUMN_SIZE, COLUMN_MIME_TYPE and COLUMN_LAST_MODIFIED.
If NO_CACHE, don't cache the file status; just return the
entry. */
private StatCacheEntry
cacheFileStatus (String documentId, CacheToplevel toplevel,
Cursor cursor)
Cursor cursor, boolean no_cache)
{
StatCacheEntry entry;
int flagsIndex, columnIndex, typeIndex;
@ -482,7 +485,8 @@ private static final class CacheEntry
entry.mtime = cursor.getLong (mtimeIndex);
/* Finally, add this entry to the cache and return. */
toplevel.statCache.put (documentId, entry);
if (!no_cache)
toplevel.statCache.put (documentId, entry);
return entry;
}
@ -546,7 +550,7 @@ private static final class CacheEntry
directory listing is being requested, it's very likely
that a series of calls for file status will follow. */
cacheFileStatus (id, toplevel, cursor);
cacheFileStatus (id, toplevel, cursor, false);
/* If this constituent is a directory, don't cache any
information about it. It cannot be cached without
@ -1217,7 +1221,7 @@ type is either NULL (in which case id should also be NULL) or
private long[]
statDocument1 (String uri, String documentId,
CancellationSignal signal)
CancellationSignal signal, boolean noCache)
{
Uri uriObject, tree;
String[] projection;
@ -1266,7 +1270,8 @@ type is either NULL (in which case id should also be NULL) or
if (!cursor.moveToFirst ())
return null;
cache = cacheFileStatus (documentId, toplevel, cursor);
cache = cacheFileStatus (documentId, toplevel, cursor,
noCache);
}
finally
{
@ -1332,18 +1337,22 @@ type is either NULL (in which case id should also be NULL) or
last modification to this file in milliseconds since 00:00,
January 1st, 1970.
If NOCACHE, refrain from placing the file status within the
status cache.
OperationCanceledException and other typical exceptions may be
signaled upon receiving async input or other errors. */
public long[]
statDocument (final String uri, final String documentId)
statDocument (final String uri, final String documentId,
final boolean noCache)
{
return (long[]) runObjectFunction (new SafObjectFunction () {
@Override
public Object
runObject (CancellationSignal signal)
{
return statDocument1 (uri, documentId, signal);
return statDocument1 (uri, documentId, signal, noCache);
}
});
}

7
java/org/gnu/emacs/EmacsService.java
View file

@ -1389,11 +1389,14 @@ else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
last modification to this file in milliseconds since 00:00,
January 1st, 1970.
If NOCACHE, refrain from placing the file status within the
status cache.
OperationCanceledException and other typical exceptions may be
signaled upon receiving async input or other errors. */
public long[]
statDocument (String uri, String documentId)
statDocument (String uri, String documentId, boolean noCache)
{
/* Start the thread used to run SAF requests if it isn't already
running. */
@ -1404,7 +1407,7 @@ else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
storageThread.start ();
}
return storageThread.statDocument (uri, documentId);
return storageThread.statDocument (uri, documentId, noCache);
}
/* Find out whether Emacs has access to the document designated by

2
src/android.c
View file

@ -1564,7 +1564,7 @@ android_init_emacs_service (void)
"(Ljava/lang/String;Ljava/lang/String;)"
"Ljava/lang/String;");
FIND_METHOD (stat_document, "statDocument",
"(Ljava/lang/String;Ljava/lang/String;)[J");
"(Ljava/lang/String;Ljava/lang/String;Z)[J");
FIND_METHOD (access_document, "accessDocument",
"(Ljava/lang/String;Ljava/lang/String;Z)I");
FIND_METHOD (open_document_directory, "openDocumentDirectory",

26
src/androidvfs.c
View file

@ -3932,12 +3932,15 @@ android_saf_exception_check (int n, ...)
/* Return file status for the document designated by ID_NAME within
the document tree identified by URI_NAME.
If NO_CACHE, don't cache the resulting file status. Enable this
option if the file status is subject to imminent change.
If the file status is available, place it within *STATB and return
0. If not, return -1 and set errno to EPERM. */
static int
android_saf_stat (const char *uri_name, const char *id_name,
struct stat *statb)
struct stat *statb, bool no_cache)
{
jmethodID method;
jstring uri, id;
@ -3969,10 +3972,12 @@ android_saf_stat (const char *uri_name, const char *id_name,
/* Try to retrieve the file status. */
method = service_class.stat_document;
inside_saf_critical_section = true;
status = (*android_java_env)->CallNonvirtualObjectMethod (android_java_env,
emacs_service,
service_class.class,
method, uri, id);
status
= (*android_java_env)->CallNonvirtualObjectMethod (android_java_env,
emacs_service,
service_class.class,
method, uri, id,
(jboolean) no_cache);
inside_saf_critical_section = false;
/* Check for exceptions and release unneeded local references. */
@ -5076,7 +5081,7 @@ android_saf_tree_stat (struct android_vnode *vnode,
vp = (struct android_saf_tree_vnode *) vnode;
return android_saf_stat (vp->tree_uri, vp->document_id,
statb);
statb, false);
}
static int
@ -5716,10 +5721,15 @@ android_saf_file_open (struct android_vnode *vnode, int flags,
ANDROID_DELETE_LOCAL_REF (descriptor);
/* Try to retrieve the modification time of this file from the
content provider. */
content provider.
Refrain from introducing the file status into the file status
cache if FLAGS & O_RDWR or FLAGS & O_WRONLY: the cached file
status will contain a size and modification time inconsistent
with the result of any modifications that later transpire. */
if (!android_saf_stat (vp->tree_uri, vp->document_id,
&statb))
&statb, write))
info->mtime = get_stat_mtime (&statb);
else
info->mtime = invalid_timespec ();