daemon: remove from db files with dtime older than a given date.

LightMediaScanner will not delete the database entries for files that
are gone, instead it will mark the 'dtime' column with current
timestamp. This allows fast restore of files from a removable media,
but can grow the database too much if these are never purged from time
to time.

This commit introduces --delete-older-than=DAYS (-d=DAYS) that will
always purge entries older than the given number of days, or negative
value to disable this behavior.

diff --git a/src/bin/lightmediascannerd.c b/src/bin/lightmediascannerd.c
index e77f352..4dde4e6 100644 (file)
--- a/src/bin/lightmediascannerd.c
+++ b/src/bin/lightmediascannerd.c
@@ -11,6 +11,7 @@ static char **charsets = NULL;
 static GHashTable *categories = NULL;
 static int commit_interval = 100;
 static int slave_timeout = 60;
+static int delete_older_than = 30;
 static gboolean vacuum = FALSE;
 static gboolean startup_scan = FALSE;
 
@@ -147,6 +148,47 @@ end:
 }
 
 static void
+do_delete_old(void)
+{
+    const char sql[] = "DELETE FROM files WHERE dtime > 0 and dtime <= ?";
+    sqlite3 *db;
+    sqlite3_stmt *stmt;
+    gint64 dtime;
+    int ret;
+
+    ret = sqlite3_open_v2(db_path, &db, SQLITE_OPEN_READWRITE, NULL);
+    if (ret != SQLITE_OK) {
+        g_warning("Couldn't open '%s': %s", db_path, sqlite3_errmsg(db));
+        goto end;
+    }
+
+    if (sqlite3_prepare_v2(db, sql, -1, &stmt, NULL) != SQLITE_OK) {
+        g_warning("Couldn't prepare delete old from %s: %s",
+                  db_path, sqlite3_errmsg(db));
+        goto end;
+    }
+
+    dtime = (gint64)time(NULL) - delete_older_than * (24 * 60 * 60);
+    if (sqlite3_bind_int64(stmt, 1, dtime) != SQLITE_OK) {
+        g_warning("Couldn't bind delete old dtime '%lld'from %s: %s",
+                  dtime, db_path, sqlite3_errmsg(db));
+        goto cleanup;
+    }
+
+    ret = sqlite3_step(stmt);
+    if (ret != SQLITE_DONE)
+        g_warning("Couldn't run SQL delete old dtime '%lld', ret=%d: %s",
+                  dtime, ret, sqlite3_errmsg(db));
+
+cleanup:
+    sqlite3_reset(stmt);
+    sqlite3_finalize(stmt);
+
+end:
+    sqlite3_close(db);
+}
+
+static void
 do_vacuum(void)
 {
     const char sql[] = "VACUUM";
@@ -658,6 +700,12 @@ scanner_thread_work(gpointer data)
 
     g_debug("finished scanner thread");
 
+    if (delete_older_than >= 0) {
+        g_debug("Delete from DB files with dtime older than %d days.",
+                delete_older_than);
+        do_delete_old();
+    }
+
     if (vacuum) {
         GTimer *timer = g_timer_new();
 
@@ -1157,6 +1205,16 @@ main(int argc, char *argv[])
          "Number of seconds to wait for slave to reply, otherwise kills it. "
          "Defaults to 60.",
          "SECONDS"},
+        {"delete-older-than", 'd', 0, G_OPTION_ARG_INT, &delete_older_than,
+         "Delete from database files that have 'dtime' older than the given "
+         "number of DAYS. If not specified LightMediaScanner will keep the "
+         "files in the database even if they are gone from the file system "
+         "and if they appear again and have the same 'mtime' and 'size' "
+         "it will be restored ('dtime' set to 0) without the need to parse "
+         "the file again (much faster). This is useful for removable media. "
+         "Use a negative number to disable this behavior. "
+         "Defaults to 30.",
+         "DAYS"},
         {"vacuum", 'V', 0, G_OPTION_ARG_NONE, &vacuum,
          "Execute SQL VACUUM after every scan.", NULL},
         {"startup-scan", 'S', 0, G_OPTION_ARG_NONE, &startup_scan,
@@ -1272,6 +1330,7 @@ main(int argc, char *argv[])
     g_debug("db-path: %s", db_path);
     g_debug("commit-interval: %d files", commit_interval);
     g_debug("slave-timeout: %d seconds", slave_timeout);
+    g_debug("delete-older-than: %d days", delete_older_than);
 
     if (charsets) {
         char *tmp = g_strjoinv(", ", charsets);