Add support for piping entry ids into command

bin/core/imag-view/src/main.rs

@@ -46,6 +46,7 @@ extern crate libimagstore;
 
 use std::collections::BTreeMap;
 use std::io::Write;
+use std::io::Read;
 use std::path::PathBuf;
 use std::process::Command;
 use std::process::exit;
@@ -187,13 +188,35 @@ fn main() {
 }
 
 fn entry_ids(rt: &Runtime) -> Vec<StoreId> {
-    rt.cli()
-        .values_of("id")
-        .unwrap() // enforced by clap
-        .map(PathBuf::from)
-        .map(PathBuf::into_storeid)
-        .trace_unwrap_exit(1)
-        .collect()
+    match rt.cli().values_of("id") {
+        Some(pathes) => pathes
+            .map(PathBuf::from)
+            .map(PathBuf::into_storeid)
+            .trace_unwrap_exit(1)
+            .collect(),
+
+        None => if rt.cli().is_present("entries-from-stdin") {
+            let stdin = rt.stdin().unwrap_or_else(|| {
+                error!("Cannot get handle to stdin");
+                ::std::process::exit(1)
+            });
+
+            let mut buf = String::new();
+            let _ = stdin.lock().read_to_string(&mut buf).unwrap_or_else(|_| {
+                error!("Failed to read from stdin");
+                ::std::process::exit(1)
+            });
+
+            buf.lines()
+                .map(PathBuf::from)
+                .map(PathBuf::into_storeid)
+                .trace_unwrap_exit(1)
+                .collect()
+        } else {
+            error!("Something weird happened. I was not able to find the path of the entries to edit");
+            ::std::process::exit(1)
+        }
+    }
 }
 
 fn create_tempfile_for<'a>(entry: &FileLockEntry<'a>, view_header: bool, hide_content: bool)

bin/core/imag-view/src/ui.rs

@@ -17,17 +17,28 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 //
 
-use clap::{Arg, App, SubCommand};
+use clap::{Arg, ArgGroup, App, SubCommand};
 
 pub fn build_ui<'a>(app: App<'a, 'a>) -> App<'a, 'a> {
     app
+        .arg(Arg::with_name("entries-from-stdin")
+             .long("ids-from-stdin")
+             .short("I")
+             .required(false)
+             .multiple(true)
+             .help("The entry/entries are piped in via stdin"))
+
         .arg(Arg::with_name("id")
-            .index(1)
-            .takes_value(true)
-            .required(true)
-            .multiple(true)
-            .help("View this entry at this store path")
-            .value_name("ID"))
+             .index(1)
+             .takes_value(true)
+             .required(false)
+             .multiple(true)
+             .help("View these entries at this store path")
+             .value_name("IDs"))
+
+        .group(ArgGroup::with_name("input-method")
+               .args(&["id", "entries-from-stdin"])
+               .required(true))
 
         .arg(Arg::with_name("view-header")
             .long("header")