windows powerfail signal: stop indexing only on resume and topdirs change

src/common/rclinit.cpp

@@ -168,12 +168,14 @@ LRESULT CALLBACK MainWndProc(HWND hwnd , UINT msg , WPARAM wParam,
     case WM_POWERBROADCAST:
     {
         LOGDEB("MainWndProc: got powerbroadcast message\n");
-        // We always try to end an indexing operation, independantly
-        // of the kind of event. Mounted volumes may have changed
-        // etc. Using SIGTERM just to have something different from
-        // the other messages
+        // This gets specific processing because we want to check the
+        // state of topdirs on resuming indexing (in case a mounted
+        // volume went away).
         if (l_sigcleanup) {
-            l_sigcleanup(SIGTERM);
+            if (wParam == PBT_APMRESUMEAUTOMATIC ||
+                wParam == PBT_APMRESUMESUSPEND) {
+                l_sigcleanup(RCLSIG_RESUME);
+            }
         }
     }
     break;

src/common/rclinit.h

@@ -41,6 +41,14 @@ class RclConfig;
  */
 enum RclInitFlags {RCLINIT_NONE = 0, RCLINIT_DAEMON = 1, RCLINIT_IDX = 2,
                    RCLINIT_PYTHON = 4};
+// Kinds of termination requests, in addition to the normal signal
+// values. Passed as type int to sigcleanup() when it is not invoked
+// directly as a sig handler. Note that because of the existence of
+// sigset_t, we are pretty sure that no signals can have a high value
+enum RclSigKind {
+    // System resume from sleep
+    RCLSIG_RESUME = 1002};
+                 
 extern RclConfig *recollinit(int flags,
                              void (*cleanup)(void), void (*sigcleanup)(int),
                              std::string& reason, const std::string *argcnf = 0);

src/index/fsindexer.cpp

@@ -172,21 +172,6 @@ bool FsIndexer::init()
     return true;
 }
 
-// Check if path is either non-existing or an empty directory.
-static bool path_empty(const string& path)
-{
-    if (path_isdir(path)) {
-        string reason;
-        std::set<string> entries;
-        if (!readdir(path, reason, entries) || entries.empty()) {
-            return true;
-        }
-        return false;
-    } else {
-        return !path_exists(path);
-    }
-}
-
 // Recursively index each directory in the topdirs:
 bool FsIndexer::index(int flags)
 {

src/index/recollindex.cpp

@@ -174,12 +174,43 @@ private:
 };
 static MyUpdater *updater;
 
+// This holds the state of topdirs (exist+nonempty) on indexing
+// startup. If it changes after a resume from sleep we interrupt the
+// indexing (the assumption being that a volume has been mounted or
+// unmounted while we slept). This is not foolproof as the user can
+// always pull out a removable volume while we work. It just avoids a
+// harmful purge in a common case.
+static vector<string> o_topdirs;
+static vector<bool> o_topdirs_emptiness;
+
+bool topdirs_state(vector<bool> tdlstate)
+{
+    tdlstate.clear();
+    for (const auto& dir : o_topdirs) {
+        tdlstate.push_back(path_empty(dir));
+    }
+}
+    
 static void sigcleanup(int sig)
 {
-    cerr << "Recollindex: got signal " << sig << ", registering stop request\n";
-    LOGDEB("Got signal " << sig << ", registering stop request\n");
-    CancelCheck::instance().setCancel();
-    stopindexing = 1;
+    if (sig == RCLSIG_RESUME) {
+        vector<bool> emptiness;
+        topdirs_state(emptiness);
+        if (emptiness != o_topdirs_emptiness) {
+            string msg = "Recollindex: resume: topdirs state changed while "
+                "we were sleeping\n";
+            cerr << msg;
+            LOGDEB(msg);
+            CancelCheck::instance().setCancel();
+            stopindexing = 1;
+        }
+    } else {
+        cerr << "Recollindex: got signal " << sig <<
+            ", registering stop request\n";
+        LOGDEB("Got signal " << sig << ", registering stop request\n");
+        CancelCheck::instance().setCancel();
+        stopindexing = 1;
+    }
 }
 
 static void makeIndexerOrExit(RclConfig *config, bool inPlaceReset)
@@ -330,8 +361,7 @@ static bool createstemdb(RclConfig *config, const string &lang)
 // match existing files or directories. Warn if they don't
 static bool checktopdirs(RclConfig *config, vector<string>& nonexist)
 {
-    vector<string> tdl;
-    if (!config->getConfParam("topdirs", &tdl)) {
+    if (!config->getConfParam("topdirs", &o_topdirs)) {
         cerr << "No 'topdirs' parameter in configuration\n";
         LOGERR("recollindex:No 'topdirs' parameter in configuration\n");
         return false;
@@ -343,7 +373,7 @@ static bool checktopdirs(RclConfig *config, vector<string>& nonexist)
     if (config->getConfParam("monitordirs", &mondirs)) {
         for (const auto& sub : mondirs) {
             bool found{false};
-            for (const auto& top : tdl) {
+            for (const auto& top : o_topdirs) {
                 if (path_isdesc(top, sub)) {
                     found = true;
                     break;
@@ -358,24 +388,24 @@ static bool checktopdirs(RclConfig *config, vector<string>& nonexist)
             }
         }
     }
-
     
-    for (vector<string>::iterator it = tdl.begin(); it != tdl.end(); it++) {
-	*it = path_tildexpand(*it);
-        if (!it->size() || !path_isabsolute(*it)) {
-            if ((*it)[0] == '~') {
-                cerr << "Tilde expansion failed: " << *it << endl;
-                LOGERR("recollindex: tilde expansion failed: " << *it << "\n");
+    for (auto& dir : o_topdirs) {
+	dir = path_tildexpand(dir);
+        if (!dir.size() || !path_isabsolute(dir)) {
+            if (dir[0] == '~') {
+                cerr << "Tilde expansion failed: " << dir << endl;
+                LOGERR("recollindex: tilde expansion failed: " << dir << "\n");
             } else {
-                cerr << "Not an absolute path: " << *it << endl;
-                LOGERR("recollindex: not an absolute path: " << *it << "\n");
+                cerr << "Not an absolute path: " << dir << endl;
+                LOGERR("recollindex: not an absolute path: " << dir << "\n");
             }
             return false;
         }
-        if (!path_exists(*it)) {
-            nonexist.push_back(*it);
+        if (!path_exists(dir)) {
+            nonexist.push_back(dir);
         }
     }
+    topdirs_state(o_topdirs_emptiness);
 
     // We'd like to check skippedPaths too, but these are wildcard
     // exprs, so reasonably can't
@@ -895,4 +925,3 @@ int main(int argc, char **argv)
 	return !status;
     }
 }
-

src/utils/rclutil.cpp

@@ -132,6 +132,21 @@ string path_wingettempfilename(TCHAR *pref)
 
 #endif // _WIN32
 
+// Check if path is either non-existing or an empty directory.
+bool path_empty(const string& path)
+{
+    if (path_isdir(path)) {
+        string reason;
+        std::set<string> entries;
+        if (!readdir(path, reason, entries) || entries.empty()) {
+            return true;
+        }
+        return false;
+    } else {
+        return !path_exists(path);
+    }
+}
+
 string path_defaultrecollconfsubdir()
 {
 #ifdef _WIN32

src/utils/rclutil.h

@@ -30,6 +30,8 @@ extern void rclutil_init_mt();
 
 /// Sub-directory for default recoll config (e.g: .recoll)
 extern std::string path_defaultrecollconfsubdir();
+// Check if path is either non-existing or an empty directory.
+extern bool path_empty(const std::string& path);
 
 /// e.g. /usr/share/recoll. Depends on OS and config
 extern const std::string& path_pkgdatadir();