Install Dosh binaries atomically

install.ps1

@@ -141,6 +141,20 @@ function Verify-ArchiveVersion($ExtractDir, $Url) {
     }
 }
 
+function Install-Binary($Source, $Destination) {
+    $dir = Split-Path -Parent $Destination
+    $name = Split-Path -Leaf $Destination
+    $tmp = Join-Path $dir ".$name.tmp.$PID"
+    Copy-Item $Source $tmp -Force
+    try {
+        Move-Item $tmp $Destination -Force
+    }
+    catch {
+        Remove-Item $tmp -Force -ErrorAction SilentlyContinue
+        throw
+    }
+}
+
 $bindir = Join-Path $Prefix "bin"
 $configDir = Join-Path $HOME ".config\dosh"
 New-Item -ItemType Directory -Force -Path $bindir, $configDir | Out-Null
@@ -168,9 +182,9 @@ function Install-Prebuilt {
             if (-not $found) {
                 throw "prebuilt archive missing $bin"
             }
-            Copy-Item $found.FullName (Join-Path $bindir $bin) -Force
+            Install-Binary $found.FullName (Join-Path $bindir $bin)
         }
-        Copy-Item (Join-Path $bindir "dosh-client.exe") (Join-Path $bindir "dosh.exe") -Force
+        Install-Binary (Join-Path $bindir "dosh-client.exe") (Join-Path $bindir "dosh.exe")
         return $true
     }
     catch {
@@ -202,9 +216,9 @@ function Install-FromSource {
     try {
         Push-Location $src
         cargo build --release --bin dosh-client --bin dosh-bench
-        Copy-Item "target\release\dosh-client.exe" (Join-Path $bindir "dosh-client.exe") -Force
-        Copy-Item "target\release\dosh-client.exe" (Join-Path $bindir "dosh.exe") -Force
-        Copy-Item "target\release\dosh-bench.exe" (Join-Path $bindir "dosh-bench.exe") -Force
+        Install-Binary "target\release\dosh-client.exe" (Join-Path $bindir "dosh-client.exe")
+        Install-Binary "target\release\dosh-client.exe" (Join-Path $bindir "dosh.exe")
+        Install-Binary "target\release\dosh-bench.exe" (Join-Path $bindir "dosh-bench.exe")
     }
     finally {
         Pop-Location