preview of diff files & iso content require diff & isoinfo installed

3 files changed, 19 insertions, 6 deletions

diff --git a/src/constant_strings_paths.rs b/src/constant_strings_paths.rs
index 6cdb8bd..d67a90d 100644
--- a/src/constant_strings_paths.rs
+++ b/src/constant_strings_paths.rs
@@ -164,3 +164,7 @@ pub const UEBERZUG: &str = "ueberzug";
 pub const JUPYTER: &str = "jupyter";
 /// pandoc. used to preview .doc & .odb documents
 pub const PANDOC: &str = "pandoc";
+/// diff. used to preview diff between files
+pub const DIFF: &str = "diff";
+/// isoinfo. used to preview iso file content
+pub const ISOINFO: &str = "isoinfo";
diff --git a/src/event_exec.rs b/src/event_exec.rs
index 815aa3d..3a86a2b 100644
--- a/src/event_exec.rs
+++ b/src/event_exec.rs
@@ -11,6 +11,7 @@ use which::which;
 use crate::action_map::ActionMap;
 use crate::completion::InputCompleted;
 use crate::config::Colors;
+use crate::constant_strings_paths::DIFF;
 use crate::constant_strings_paths::MEDIAINFO;
 use crate::constant_strings_paths::NITROGEN;
 use crate::constant_strings_paths::SSHFS_EXECUTABLE;
@@ -828,6 +829,10 @@ impl EventAction {
 
     /// Display a diff between the first 2 flagged files or dir.
     pub fn diff(status: &mut Status) -> Result<()> {
+        if !is_program_in_path(DIFF) {
+            write_log_line(format!("{DIFF} isn't installed"));
+            return Ok(());
+        }
         if status.flagged.len() < 2 {
             return Ok(());
         };
diff --git a/src/preview.rs b/src/preview.rs
index 8b24579..bd6ff21 100644
--- a/src/preview.rs
+++ b/src/preview.rs
@@ -19,7 +19,9 @@ use tuikit::attr::{Attr, Color};
 use users::UsersCache;
 
 use crate::config::Colors;
-use crate::constant_strings_paths::{JUPYTER, MEDIAINFO, PANDOC, THUMBNAIL_PATH, UEBERZUG};
+use crate::constant_strings_paths::{
+    DIFF, ISOINFO, JUPYTER, MEDIAINFO, PANDOC, THUMBNAIL_PATH, UEBERZUG,
+};
 use crate::content_window::ContentWindow;
 use crate::decompress::list_files_zip;
 use crate::fileinfo::{FileInfo, FileKind};
@@ -97,7 +99,9 @@ impl Preview {
                 e if is_ext_svg(e) && is_program_in_path(UEBERZUG) => {
                     Ok(Self::Ueberzug(Ueberzug::svg_thumbnail(&file_info.path)?))
                 }
-                e if is_ext_iso(e) => Ok(Self::Iso(Iso::new(&file_info.path)?)),
+                e if is_ext_iso(e) && is_program_in_path(ISOINFO) => {
+                    Ok(Self::Iso(Iso::new(&file_info.path)?))
+                }
                 e if is_ext_notebook(e) && is_program_in_path(JUPYTER) => {
                     Ok(Self::notebook(&file_info.path)
                         .context("Preview: Couldn't parse notebook")?)
@@ -886,11 +890,11 @@ pub struct Diff {
 impl Diff {
     pub fn new(first_path: &str, second_path: &str) -> Result<Self> {
         let content: Vec<String> =
-            execute_and_capture_output_without_check("diff", &[first_path, second_path])?
+            execute_and_capture_output_without_check(DIFF, &[first_path, second_path])?
                 .lines()
                 .map(|s| s.to_owned())
                 .collect();
-        info!("diff:\n{content:?}");
+        info!("{DIFF}:\n{content:?}");
 
         Ok(Self {
             length: content.len(),
@@ -912,11 +916,11 @@ impl Iso {
     fn new(path: &Path) -> Result<Self> {
         let path = path.to_str().context("couldn't parse the path")?;
         let content: Vec<String> =
-            execute_and_capture_output_without_check("isoinfo", &["-l", "-i", path])?
+            execute_and_capture_output_without_check(ISOINFO, &["-l", "-i", path])?
                 .lines()
                 .map(|s| s.to_owned())
                 .collect();
-        info!("isofino:\n{content:?}");
+        info!("{ISOINFO}:\n{content:?}");
 
         Ok(Self {
             length: content.len(),