Add hook for checking whether a about-to-be-deleted entry still has links

libimagstorestdhook/src/denylinkeddelete.rs

@@ -0,0 +1,122 @@
+//
+// imag - the personal information management suite for the commandline
+// Copyright (C) 2015, 2016 Matthias Beyer <mail@beyermatthias.de> and contributors
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; version
+// 2.1 of the License.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+//
+
+use std::path::PathBuf;
+
+use toml::Value;
+
+use libimagstore::hook::Hook;
+use libimagstore::hook::error::HookErrorKind as HEK;
+use libimagstore::hook::accessor::HookDataAccessor as HDA;
+use libimagstore::hook::accessor::HookDataAccessorProvider;
+use libimagstore::hook::accessor::NonMutableHookDataAccessor;
+use libimagstore::hook::result::HookResult;
+use libimagstore::store::FileLockEntry;
+use libimagentrylink::internal::InternalLinker;
+use libimagerror::trace::trace_error;
+
+
+mod error {
+    generate_error_imports!();
+    generate_error_types!(NoLinksLeftCheckerHookError, NoLinksLeftCheckerHookErrorKind,
+        LinksLeft => "The entry has links and therefor cannot be deleted."
+    );
+}
+use self::error::NoLinksLeftCheckerHookError as NLLCHE;
+use self::error::NoLinksLeftCheckerHookErrorKind as NLLCHEK;
+use self::error::MapErrInto;
+
+#[derive(Debug, Clone)]
+pub struct DenyDeletionOfLinkedEntriesHook {
+    abort: bool
+}
+
+impl DenyDeletionOfLinkedEntriesHook {
+
+    pub fn new() -> DenyDeletionOfLinkedEntriesHook {
+        DenyDeletionOfLinkedEntriesHook {
+            abort: true // by default, this hook aborts actions
+        }
+    }
+
+}
+
+impl Hook for DenyDeletionOfLinkedEntriesHook {
+
+    fn name(&self) -> &'static str {
+        "stdhook_linked_entries_cannot_be_deleted"
+    }
+
+    fn set_config(&mut self, v: &Value) {
+        self.abort = match v.lookup("aborting") {
+            Some(&Value::Boolean(b)) => b,
+            Some(_) => {
+                warn!("Configuration error, 'aborting' must be a Boolean (true|false).");
+                warn!("Assuming 'true' now.");
+                true
+            },
+            None => {
+                warn!("No key 'aborting' - Assuming 'true'");
+                true
+            },
+        };
+    }
+
+}
+
+impl HookDataAccessorProvider for DenyDeletionOfLinkedEntriesHook {
+
+    fn accessor(&self) -> HDA {
+        HDA::NonMutableAccess(self)
+    }
+
+}
+
+impl NonMutableHookDataAccessor for DenyDeletionOfLinkedEntriesHook {
+
+    fn access(&self, fle: &FileLockEntry) -> HookResult<()> {
+        use libimagutil::warn_result::*;
+        use libimagutil::debug_result::*;
+        use libimagerror::trace::MapErrTrace;
+        use libimagerror::into::IntoError;
+        use libimagstore::hook::error::MapErrInto;
+
+        debug!("[NO LINKS LEFT CHECKER HOOK] {:?}", fle.get_location());
+
+        let n = fle
+            .get_internal_links()
+            .map(|i| i.count())
+            .map_warn_err_str("[NO LINKS LEFT CHECKER HOOK]: Cannot get internal links")
+            .map_warn_err_str("[NO LINKS LEFT CHECKER HOOK]: Assuming 1 to automatically abort")
+            .map_dbg_err_str("[NO LINKS LEFT CHECKER HOOK]: Printing trace now")
+            .map_err_trace()
+            .unwrap_or(1);
+
+        if n > 0 {
+            Err(NLLCHEK::LinksLeft.into_error())
+                .map_err(Box::new)
+                .map_err(|e| HEK::HookExecutionError.into_error_with_cause(e))
+        } else {
+            Ok(())
+        }
+    }
+
+}
+
+

libimagstorestdhook/src/lib.rs

@@ -45,6 +45,7 @@ extern crate libimaginteraction;
 extern crate libimagutil;
 
 pub mod debug;
+pub mod denylinkeddelete;
 pub mod flock;
 pub mod linkverify;
 pub mod vcs;