ipc: Invoke GnuPG in background without flashing terminals.

See relevant MR on sequoia-octopus-lib:
https://gitlab.com/sequoia-pgp/sequoia-octopus-librnp/-/merge_requests/42

2 files changed, 25 insertions, 4 deletions

diff --git a/ipc/src/gnupg.rs b/ipc/src/gnupg.rs
index 1d6b49bf..f008d012 100644
--- a/ipc/src/gnupg.rs
+++ b/ipc/src/gnupg.rs
@@ -7,7 +7,6 @@ use std::convert::TryFrom;
 use std::ffi::OsStr;
 use std::ops::{Deref, DerefMut};
 use std::path::{Path, PathBuf};
-use std::process::Command;
 
 use futures::{Future, Stream};
 
@@ -132,7 +131,9 @@ impl Context {
                 Mode::Windows => "--windows",
                 Mode::Unix => "--unix",
             };
-            Command::new("cygpath").arg(conversion_type).arg(path.as_ref())
+            crate::new_background_command("cygpath")
+		.arg(conversion_type)
+		.arg(path.as_ref())
                 .output()
                 .map_err(Into::into)
                 .and_then(|out|
@@ -162,7 +163,7 @@ impl Context {
         let nl = |&c: &u8| c as char == '\n';
         let colon = |&c: &u8| c as char == ':';
 
-        let mut gpgconf = Command::new("gpgconf");
+        let mut gpgconf = crate::new_background_command("gpgconf");
         if let Some(homedir) = homedir {
             gpgconf.arg("--homedir").arg(homedir);
 
diff --git a/ipc/src/lib.rs b/ipc/src/lib.rs
index dbc9f965..b0bb3dee 100644
--- a/ipc/src/lib.rs
+++ b/ipc/src/lib.rs
@@ -245,7 +245,7 @@ impl Descriptor {
     }
 
     fn fork(&self, listener: TcpListener) -> Result<()> {
-        let mut cmd = Command::new(&self.executable);
+        let mut cmd = new_background_command(&self.executable);
         cmd
             .arg("--home")
             .arg(self.ctx.home())
@@ -533,3 +533,23 @@ fn wsa_cleanup() {
         let _ = unsafe { winsock2::WSACleanup() };
     }
 }
+
+pub(crate) fn new_background_command<S>(program: S) -> Command
+where
+    S: AsRef<std::ffi::OsStr>,
+{
+    let command = Command::new(program);
+
+    #[cfg(windows)]
+    let command = {
+        use std::os::windows::process::CommandExt;
+
+        // see https://docs.microsoft.com/en-us/windows/win32/procthread/process-creation-flags
+        const CREATE_NO_WINDOW: u32 = 0x08000000;
+        let mut command = command;
+        command.creation_flags(CREATE_NO_WINDOW);
+        command
+    };
+
+    command
+}