Add Open/Save mode to the file selection dialogfile-selection

This patch adds the option to set a FileSelectionMode, either Open or
Save.  Not all backends might support this – currently, only zenity and
kdialog do.  Per default, the Open mode is used (as before).

2 files changed, 15 insertions, 4 deletions

diff --git a/src/backends/kdialog.rs b/src/backends/kdialog.rs
index e556ddf..21928f8 100644
--- a/src/backends/kdialog.rs
+++ b/src/backends/kdialog.rs
@@ -4,7 +4,9 @@
 
 use std::process;
 
-use crate::{Choice, Error, FileSelection, Input, Message, Password, Question, Result};
+use crate::{
+    Choice, Error, FileSelection, FileSelectionMode, Input, Message, Password, Question, Result,
+};
 
 /// Subprocess exit codes
 ///
@@ -139,7 +141,11 @@ impl super::Backend for KDialog {
 
     fn show_file_selection(&self, file_selection: &FileSelection) -> Result<Option<String>> {
         let dir = file_selection.path_to_string().ok_or("path not valid")?;
-        let args = vec!["--getopenfilename", &dir];
+        let option = match file_selection.mode {
+            FileSelectionMode::Open => "--getopenfilename",
+            FileSelectionMode::Save => "--getsavefilename",
+        };
+        let args = vec![option, &dir];
         self.execute(args, &file_selection.title)
             .and_then(get_stdout)
     }
diff --git a/src/backends/zenity.rs b/src/backends/zenity.rs
index 4ee7785..ac0f98f 100644
--- a/src/backends/zenity.rs
+++ b/src/backends/zenity.rs
@@ -3,7 +3,9 @@
 
 use std::process;
 
-use crate::{Choice, Error, FileSelection, Input, Message, Password, Question, Result};
+use crate::{
+    Choice, Error, FileSelection, FileSelectionMode, Input, Message, Password, Question, Result,
+};
 
 /// The `zenity` backend.
 ///
@@ -166,7 +168,10 @@ impl super::Backend for Zenity {
 
     fn show_file_selection(&self, file_selection: &FileSelection) -> Result<Option<String>> {
         let dir = file_selection.path_to_string().ok_or("path not valid")?;
-        let args = vec!["--file-selection", "--filename", &dir];
+        let mut args = vec!["--file-selection", "--filename", &dir];
+        if file_selection.mode == FileSelectionMode::Save {
+            args.push("--save");
+        }
         self.execute(args, &file_selection.title)
             .and_then(get_stdout)
     }