Change type of Context.dbfile to std::path::PathBuf

This change makes code more type-correct, but introduces copying: compiler
refuses to return reference to object behind Arc<RwLock>.

src/context.rs

@@ -21,9 +21,11 @@ use crate::types::*;
 use crate::x::*;
 use std::ptr;
 
+use std::path::PathBuf;
+
 pub struct Context {
     pub userdata: *mut libc::c_void,
-    pub dbfile: Arc<RwLock<*mut libc::c_char>>,
+    pub dbfile: Arc<RwLock<Option<PathBuf>>>,
     pub blobdir: Arc<RwLock<*mut libc::c_char>>,
     pub sql: Sql,
     pub inbox: Arc<RwLock<Imap>>,
@@ -55,15 +57,17 @@ pub struct RunningState {
 
 impl Context {
     pub fn has_dbfile(&self) -> bool {
-        !self.get_dbfile().is_null()
+        self.get_dbfile().is_some()
     }
 
     pub fn has_blobdir(&self) -> bool {
         !self.get_blobdir().is_null()
     }
 
-    pub fn get_dbfile(&self) -> *const libc::c_char {
-        *self.dbfile.clone().read().unwrap()
+    pub fn get_dbfile(&self) -> Option<PathBuf> {
+        (*self.dbfile.clone().read().unwrap())
+            .as_ref()
+            .map(|x| x.clone())
     }
 
     pub fn get_blobdir(&self) -> *const libc::c_char {
@@ -130,7 +134,7 @@ pub fn dc_context_new(
 ) -> Context {
     Context {
         blobdir: Arc::new(RwLock::new(std::ptr::null_mut())),
-        dbfile: Arc::new(RwLock::new(std::ptr::null_mut())),
+        dbfile: Arc::new(RwLock::new(None)),
         inbox: Arc::new(RwLock::new({
             Imap::new(
                 cb_get_config,
@@ -282,8 +286,7 @@ pub unsafe fn dc_close(context: &Context) {
 
     context.sql.close(context);
     let mut dbfile = context.dbfile.write().unwrap();
-    free(*dbfile as *mut libc::c_void);
-    *dbfile = ptr::null_mut();
+    *dbfile = None;
     let mut blobdir = context.blobdir.write().unwrap();
     free(*blobdir as *mut libc::c_void);
     *blobdir = ptr::null_mut();
@@ -302,7 +305,7 @@ pub unsafe fn dc_open(context: &Context, dbfile: &str, blobdir: Option<&str>) ->
     if 0 != dc_is_open(context) {
         return false;
     }
-    *context.dbfile.write().unwrap() = dbfile.strdup();
+    *context.dbfile.write().unwrap() = Some(PathBuf::from(dbfile));
     if blobdir.is_some() && !blobdir.unwrap().is_empty() {
         let dir = dc_ensure_no_slash_safe(blobdir.unwrap()).strdup();
         *context.blobdir.write().unwrap() = dir;
@@ -446,11 +449,10 @@ pub unsafe fn dc_get_info(context: &Context) -> *mut libc::c_char {
         real_msgs,
         deaddrop_msgs,
         contacts,
-        if context.has_dbfile() {
-            as_str(context.get_dbfile())
-        } else {
-            unset
-        },
+        context
+            .get_dbfile()
+            .as_ref()
+            .map_or(unset, |p| p.to_str().unwrap()),
         dbversion,
         if context.has_blobdir() {
             as_str(context.get_blobdir())

src/dc_imex.rs

@@ -597,7 +597,10 @@ unsafe fn import_backup(context: &Context, backup_to_import: *const libc::c_char
         0,
         "Import \"{}\" to \"{}\".",
         as_str(backup_to_import),
-        as_str(context.get_dbfile()),
+        context
+            .get_dbfile()
+            .as_ref()
+            .map_or("<<None>>", |p| p.to_str().unwrap())
     );
 
     if 0 != dc_is_configured(context) {
@@ -605,8 +608,8 @@ unsafe fn import_backup(context: &Context, backup_to_import: *const libc::c_char
         return 0;
     }
     &context.sql.close(&context);
-    dc_delete_file(context, as_path(context.get_dbfile()));
-    if dc_file_exist(context, as_path(context.get_dbfile())) {
+    dc_delete_file(context, context.get_dbfile().unwrap());
+    if dc_file_exist(context, context.get_dbfile().unwrap()) {
         error!(
             context,
             0, "Cannot import backups: Cannot delete the old file.",
@@ -617,13 +620,16 @@ unsafe fn import_backup(context: &Context, backup_to_import: *const libc::c_char
     if !dc_copy_file(
         context,
         as_path(backup_to_import),
-        as_path(context.get_dbfile()),
+        context.get_dbfile().unwrap(),
     ) {
         return 0;
     }
     /* error already logged */
     /* re-open copied database file */
-    if !context.sql.open(&context, as_path(context.get_dbfile()), 0) {
+    if !context
+        .sql
+        .open(&context, &context.get_dbfile().unwrap(), 0)
+    {
         return 0;
     }
 
@@ -742,15 +748,20 @@ unsafe fn export_backup(context: &Context, dir: *const libc::c_char) -> libc::c_
         context,
         0,
         "Backup \"{}\" to \"{}\".",
-        as_str(context.get_dbfile()),
+        context
+            .get_dbfile()
+            .as_ref()
+            .map_or("<<None>>", |p| p.to_str().unwrap()),
         as_str(dest_pathNfilename),
     );
     if dc_copy_file(
         context,
-        as_path(context.get_dbfile()),
+        context.get_dbfile().unwrap(),
         as_path(dest_pathNfilename),
     ) {
-        context.sql.open(&context, as_path(context.get_dbfile()), 0);
+        context
+            .sql
+            .open(&context, &context.get_dbfile().unwrap(), 0);
         closed = false;
         /* add all files as blobs to the database copy (this does not require the source to be locked, neigher the destination as it is used only here) */
         /*for logging only*/
@@ -906,7 +917,9 @@ unsafe fn export_backup(context: &Context, dir: *const libc::c_char) -> libc::c_
         }
     }
     if closed {
-        context.sql.open(&context, as_path(context.get_dbfile()), 0);
+        context
+            .sql
+            .open(&context, &context.get_dbfile().unwrap(), 0);
     }
     if 0 != delete_dest_file {
         dc_delete_file(context, as_path(dest_pathNfilename));