Add --mode option to built in target task

For situations where the default 'rw-------' file modes are not enough,
a (posix) mode string can be given to target. All files will get the 
mode written.

When an invalid mode is given, a warning is printed and standard 
permissions will be used.

boot/core/src/boot/core.clj

@@ -1002,10 +1002,10 @@
   (let [prev   (atom nil)
         clean! (if clean empty-dir! identity)
         dirs   (delay (mapv #(doto (io/file %) .mkdirs clean!) dirs))]
-    (fn [fs & {:keys [link]}]
+    (fn [fs & {:keys [link mode]}]
       (let [link  (when link :tmp)
             [a b] [@prev (reset! prev (output-fileset fs))]]
-        (mapv deref (for [d @dirs :let [p! (partial fs/patch! (fs/->path d) a b :link)]]
+        (mapv deref (for [d @dirs :let [p! (partial fs/patch! (fs/->path d) a b :mode mode :link)]]
                       (future (try (p! link)
                                    (catch Throwable t
                                      (if-not link (throw t) (p! nil)))))))))))

boot/core/src/boot/task/built_in.clj

@@ -22,6 +22,7 @@
    [boot.pedantic        :as pedantic])
   (:import
    [java.io File]
+   [java.nio.file.attribute PosixFilePermissions]
    [java.util Arrays]
    [java.util.concurrent LinkedBlockingQueue TimeUnit]
    [javax.tools ToolProvider DiagnosticCollector Diagnostic$Kind]))
@@ -361,16 +362,24 @@
     (core/with-post-wrap [_] @(promise))
     (core/with-pass-thru [fs] (Thread/sleep time))))
 
+(defn- mk-posix-file-permissions [posix-string]
+  (try
+    (when posix-string
+      (PosixFilePermissions/fromString posix-string))
+    (catch IllegalArgumentException _
+      (util/warn "Could not parse mode string, ignoring...\n"))))
+
 (core/deftask target
   "Writes output files to the given directory on the filesystem."
   [d dir PATH #{str} "The set of directories to write to (target)."
+   m mode VAL str    "The mode of written files in 'rwxrwxrwx' format"
    L no-link  bool   "Don't create hard links."
    C no-clean bool   "Don't clean target before writing project files."]
   (let [dir   (or (seq dir) ["target"])
         sync! (#'core/fileset-syncer dir :clean (not no-clean))]
     (core/with-pass-thru [fs]
       (util/info "Writing target dir(s)...\n")
-      (sync! fs :link (not no-link)))))
+      (sync! fs :link (not no-link) :mode (mk-posix-file-permissions mode)))))
 
 (core/deftask watch
   "Call the next handler when source files change."

boot/pod/src/boot/filesystem.clj

@@ -155,20 +155,22 @@
     (Files/setLastModifiedTime dst (FileTime/fromMillis time))))
 
 (defn copy!
-  [^Path dest path ^Path src time]
+  [^Path dest path ^Path src time mode]
   (let [dst (doto (rel dest path) mkparents!)]
     (util/dbug* "Filesystem: copying %s...\n" (string/join "/" path))
     (try (Files/copy ^Path src ^Path dst copy-opts)
          (Files/setLastModifiedTime dst (FileTime/fromMillis time))
+         (when mode (Files/setPosixFilePermissions dst mode))
          (catch java.nio.file.NoSuchFileException ex
            (util/dbug* "Filesystem: %s\n", (str ex))))))
 
 (defn link!
-  [dest path src]
+  [dest path src mode]
   (let [dst (rel dest path)]
     (util/dbug* "Filesystem: linking %s...\n" (string/join "/" path))
     (try (Files/deleteIfExists dst)
          (Files/createLink (doto dst mkparents!) src)
+         (when mode (Files/setPosixFilePermissions dst mode))
          (catch java.nio.file.NoSuchFileException ex
            (util/dbug* "Filesystem: %s\n" (str ex))))))
 
@@ -188,11 +190,11 @@
       (writer-fn os))))
 
 (defn patch!
-  [dest before after & {:keys [link]}]
+  [dest before after & {:keys [link mode]}]
   (with-let [_ (fsp/patch-result before after)]
     (doseq [[op path & [arg1 arg2]] (fsp/patch before after link)]
       (case op
         :delete (delete! dest path)
-        :write  (copy!   dest path arg1 arg2)
-        :link   (link!   dest path arg1)
+        :write  (copy!   dest path arg1 arg2 mode)
+        :link   (link!   dest path arg1 mode)
         :touch  (touch!  dest path arg1)))))