-LRN: use signal pipe instead of a semaphore

1 files changed, 68 insertions, 64 deletions

diff --git a/src/fs/fs_dirmetascan.c b/src/fs/fs_dirmetascan.c
index 6af186347..fd8ab15c4 100644
--- a/src/fs/fs_dirmetascan.c
+++ b/src/fs/fs_dirmetascan.c
@@ -102,6 +102,26 @@ struct MetaCounter
   struct MetaCounter *next;

 };

 

+struct AddDirContext;

+

+/**

+ * A structure used to hold a pointer to the tree item that is being

+ * processed.

+ * Needed to avoid changing the context for every recursive call.

+ */

+struct AddDirStack

+{

+  /**

+   * Context pointer

+   */

+  struct AddDirContext *adc;

+

+  /**

+   * Parent directory

+   */

+  struct ShareTreeItem *parent;

+};

+

 /**

  * Execution context for 'add_dir'

  * Owned by the initiator thread.

@@ -109,13 +129,11 @@ struct MetaCounter
 struct AddDirContext

 {

   /**

-   * Parent directory (used to access keyword and metadata counters,

-   * and the like).

    * After the scan is finished, it will contain a pointer to the

    * top-level directory entry in the directory tree built by the

    * scanner.

    */

-  struct ShareTreeItem *parent;

+  struct ShareTreeItem *toplevel;

 

   /**

    * Expanded filename (as given by the scan initiator).

@@ -124,15 +142,10 @@ struct AddDirContext
   char *filename_expanded;

 

   /**

-   * A synchronization privitive. Whenever its state is altered,

-   * it means that the initiator wants the scanner to wrap up.

-   * It is owned by the initiator thread.

+   * A pipe end to read signals from.

+   * Owned by the initiator thread.

    */

-#if WINDOWS

-  HANDLE stop;

-#else

-  sem_t *stop;

-#endif

+  const struct GNUNET_DISK_FileHandle *stop_read;

 

   /**

    * 1 if the scanner should stop, 0 otherwise. Set in response

@@ -164,15 +177,17 @@ struct AddDirContext
  */

 struct GNUNET_FS_DirScanner

 {

- /**

-  * A synchronization privitive that is used to signal the scanner to stop.

-  * Owned by the initiator thread.

-  */

-#if WINDOWS

-  HANDLE stop;

-#else

-  sem_t *stop;

-#endif

+  /**

+   * A pipe end to read signals from.

+   * Owned by the initiator thread.

+   */

+  const struct GNUNET_DISK_FileHandle *stop_write;

+  

+  /**

+   * A pipe transfer signals to the scanner.

+   * Owned by the initiator thread.

+   */

+  struct GNUNET_DISK_PipeHandle *stop_pipe;

 

  /**

   * A thread object for the scanner thread.

@@ -312,21 +327,14 @@ struct ProcessMetadataContext
 static int

 should_stop (struct AddDirContext *adc)

 {

-#if WINDOWS

-  if (WaitForSingleObject (adc->stop, 0) == WAIT_TIMEOUT)

-    return 0;

-  adc->do_stop = 1;

-  return 1;

-#else

-  int value;

-  sem_getvalue(adc->stop, &value);  

-  if (value > 0)

+  errno = 0;

+  char c;

+  if (GNUNET_DISK_file_read_non_blocking (adc->stop_read, &c, 1) == 1

+      || errno != EAGAIN)

   {

     adc->do_stop = 1;

-    return 1;

   }

-  return 0;

-#endif

+  return adc->do_stop;

 }

 

 /**

@@ -535,19 +543,19 @@ make_item (struct ShareTreeItem *parent)
  * @param filename name of the file to process

  */

 static void

-extract_file (struct AddDirContext *adc, const char *filename)

+extract_file (struct AddDirStack *ads, const char *filename)

 {

   struct ShareTreeItem *item;

   const char *short_fn;

 

-  item = make_item (adc->parent);

+  item = make_item (ads->parent);

 

   GNUNET_DISK_file_size (filename, &item->file_size, GNUNET_YES);

   item->is_directory = GNUNET_NO;

 

   item->meta = GNUNET_CONTAINER_meta_data_create ();

   GNUNET_FS_meta_data_extract_from_file (item->meta, filename,

-      adc->plugins);

+      ads->adc->plugins);

   GNUNET_CONTAINER_meta_data_delete (item->meta, EXTRACTOR_METATYPE_FILENAME,

       NULL, 0);

   short_fn = GNUNET_STRINGS_get_short_name (filename);

@@ -725,13 +733,14 @@ process_keywords_and_metadata (struct ProcessMetadataStackItem *stack,
  * scan.

  * TODO: find a way to make it non-recursive.

  *

- * @param cls the 'struct AddDirContext*' we're in

+ * @param cls the 'struct AddDirStack *' we're in

  * @param filename file or directory to scan

  */

 static int

 scan_directory (void *cls, const char *filename)

 {

-  struct AddDirContext *adc = cls, recurse_adc;

+  struct AddDirStack *ads = cls, recurse_ads;

+  struct AddDirContext *adc = ads->adc;

   struct stat sbuf;

   struct ShareTreeItem *item;

   const char *short_fn;

@@ -763,33 +772,31 @@ scan_directory (void *cls, const char *filename)
   }

 

   if (!S_ISDIR (sbuf.st_mode))

-    extract_file (adc, filename);

+    extract_file (ads, filename);

   else

   {

-    item = make_item (adc->parent);

+    item = make_item (ads->parent);

     item->meta = GNUNET_CONTAINER_meta_data_create ();

 

     item->is_directory = GNUNET_YES;

 

-    /* copy fields from adc */

-    recurse_adc = *adc;

-    /* replace recurse_adc contents with the ones for this directory */

-    recurse_adc.parent = item;

+    recurse_ads.adc = adc;

+    recurse_ads.parent = item;

 

     /* recurse into directory */

-    GNUNET_DISK_directory_scan (filename, &scan_directory, &recurse_adc);

+    GNUNET_DISK_directory_scan (filename, &scan_directory, &recurse_ads);

 

     short_fn = GNUNET_STRINGS_get_short_name (filename);

 

     item->filename = GNUNET_strdup (filename);

     item->short_filename = GNUNET_strdup (short_fn);

 

-    if (adc->parent == NULL)

+    if (ads->parent == NULL)

     {

       /* we're finished with the scan, make sure caller gets the top-level

        * directory pointer

        */

-      adc->parent = item;

+      adc->toplevel = item;

     }

   }

   return GNUNET_OK;

@@ -809,11 +816,9 @@ void
 GNUNET_FS_directory_scan_finish (struct GNUNET_FS_DirScanner *ds,

     int close_pipe)

 {

-#if WINDOWS

-  SetEvent (ds->stop);

-#else

-  sem_post (&ds->stop);

-#endif

+  char c = 1;

+  GNUNET_DISK_file_write (ds->stop_write, &c, 1);

+

   if (close_pipe)

   {

     if (ds->progress_read_task != GNUNET_SCHEDULER_NO_TASK)

@@ -845,16 +850,15 @@ GNUNET_FS_directory_scan_cleanup (struct GNUNET_FS_DirScanner *ds)
   GNUNET_FS_directory_scan_finish (ds, GNUNET_YES);

 #if WINDOWS

   WaitForSingleObject (ds->thread, INFINITE);

-  CloseHandle (ds->stop);

   CloseHandle (ds->thread);

 #else

   pthread_join (ds->thread, NULL);

-  sem_destroy (&ds->stop);

   pthread_detach (ds->thread);

 #endif

 

+  GNUNET_DISK_pipe_close (ds->stop_pipe);

   GNUNET_DISK_pipe_close (ds->progress_pipe);

-  result = ds->adc->parent;

+  result = ds->adc->toplevel;

   GNUNET_free (ds->adc);

   GNUNET_free (ds);

   return result;

@@ -870,7 +874,10 @@ static int
 #endif

 run_directory_scan_thread (struct AddDirContext *adc)

 {

-  scan_directory (adc, adc->filename_expanded);

+  struct AddDirStack ads;

+  ads.adc = adc;

+  ads.parent = NULL;

+  scan_directory (&ads, adc->filename_expanded);

   GNUNET_free (adc->filename_expanded);

   if (adc->plugins != NULL)

     EXTRACTOR_plugin_remove_all (adc->plugins);

@@ -1060,15 +1067,8 @@ GNUNET_FS_directory_scan_start (const char *filename,
 

   ds->adc = adc;

 

-#if WINDOWS

-  ds->stop = CreateEvent (NULL, TRUE, FALSE, NULL);

-  adc->stop = ds->stop;

-  ok = ds->stop != INVALID_HANDLE_VALUE;

-#else

-  ok = !sem_init (&ds->stop, 0, 0);

-  adc = &ds->stop;

-#endif

-  if (!ok)

+  ds->stop_pipe = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);

+  if (ds->stop_pipe == NULL)

   {

     GNUNET_free (adc);

     GNUNET_free (ds);

@@ -1076,6 +1076,10 @@ GNUNET_FS_directory_scan_start (const char *filename,
     GNUNET_DISK_pipe_close (progress_pipe);

     return NULL;

   }

+  ds->stop_write = GNUNET_DISK_pipe_handle (ds->stop_pipe,

+      GNUNET_DISK_PIPE_END_WRITE);

+  adc->stop_read = GNUNET_DISK_pipe_handle (ds->stop_pipe,

+      GNUNET_DISK_PIPE_END_READ);

 

   adc->plugins = NULL;

   if (!disable_extractor)