file/unzip: add help func with-unzip with-unzip-entry

pkgs/racket-pkgs/racket-doc/file/scribblings/unzip.scrbl

@@ -30,6 +30,20 @@ aspects of the unpacking, such as  the destination directory.
 @history[#:changed "6.0.0.3" @elem{Added the @racket[#:preserve-timestamps?] argument.}]}
 
 
+@defproc[(with-unzip [zip_file path-string?]
+                     [user_proc (-> path-string? any)])
+         void?]{
+
+A helper func to wrap unzip with clean temporay unzip files.
+
+Unzips an entire @exec{zip} archive from file path @racket[zip_file] to a temporary directory.
+
+The temporary directory is created in the @racket[zip_file]'s directory.
+
+@racket[user_proc] has this temporary directory path as its parameter.
+
+When done, delete temporay unzip files and directories.}
+
 @defproc[(make-filesystem-entry-reader
           [#:dest dest-path (or/c path-string? #f) #f]
           [#:strip-count strip-count exact-nonnegative-integer? 0]
@@ -137,6 +151,22 @@ If @racket[entry] is not in @racket[zipdir], an
 @history[#:changed "6.0.0.3" @elem{Added the @racket[#:preserve-timestamps?] argument.}]}
 
 
+@defproc[(with-unzip-entry [zip_file path-string?]
+                           [entry_file path-string?]
+                           [user_proc (-> path-string? any)])
+         void?]{
+
+A helper func to wrap unzip-entry with clean temporay unzip file.
+
+Unzip an specific entry from @racket[zip_file] to a temporary directory, @racket[entry_file] is a entry path in @racket[zip_file].
+
+The temporary directory is created in the @racket[zip_file]'s directory.
+
+@racket[user_proc] has this unzipped temporary file path as its parameter.
+
+When done, delete temporay unzip file.}
+
+
 @defproc[(path->zip-path [path path-string?]) bytes?]{
 
 Converts a file name potentially containing path separators in the current

pkgs/racket-pkgs/racket-test/tests/file/unzip.rkt

@@ -0,0 +1,26 @@
+#lang racket/base
+(require file/unzip tests/eli-tester)
+
+;; test-me.zip's directory structure is test-zip/1/data.dat
+(define (test-with-unzip)
+  (with-unzip "unzip-me.zip"
+              (lambda (tmp_dir)
+                (with-input-from-file (build-path tmp_dir "test-zip" "1" "data.dat")
+                  (lambda ()
+                    (test (read-line) => "chenxiao"))))))
+
+(define (test-with-unzip-entry)
+  (with-unzip-entry "unzip-me.zip" 
+                    (build-path "test-zip" "1" "data.dat")
+                    (lambda (tmp_file)
+                      (with-input-from-file tmp_file
+                        (lambda ()
+                          (test (read-line) => "chenxiao"))))))
+
+(define (run-tests)
+  (test-with-unzip)
+  (test-with-unzip-entry))
+
+(provide tests)
+(module+ main (tests))
+(define (tests) (test do (run-tests)))

racket/collects/file/unzip.rkt

@@ -43,6 +43,9 @@
                 . ->* .
                 any)]
 
+  [with-unzip-entry (-> path-string? path-string? (-> path-string? any) any)]
+  [with-unzip (-> path-string? (-> path-string? any) any)]
+
   [path->zip-path ((or/c string? path?) . -> . bytes?)]))
 
 ;; ===========================================================================
@@ -359,3 +362,31 @@
   (if (path? base)
       base
       (current-directory)))
+
+;; use dynamic-wind to clean temporary files
+(define (with-unzip-entry zip_file entry_file user_proc)
+  (let ([temp_dir #f])
+    (dynamic-wind
+        (lambda ()
+          (set! temp_dir (make-temporary-file "ziptmp~a" 'directory ".")))
+        (lambda ()
+          (let ([directory_entries (read-zip-directory zip_file)])
+            (unzip-entry 
+             zip_file
+             directory_entries 
+             (path->zip-path entry_file) 
+             (make-filesystem-entry-reader #:dest temp_dir #:exists 'replace))
+            (user_proc (build-path temp_dir entry_file))))
+        (lambda ()
+          (delete-directory/files temp_dir)))))
+
+(define (with-unzip zip_file user_proc)
+  (let ([temp_dir #f])
+    (dynamic-wind
+        (lambda ()
+          (set! temp_dir (make-temporary-file "ziptmp~a" 'directory ".")))
+        (lambda ()
+          (unzip zip_file (make-filesystem-entry-reader #:dest temp_dir #:exists 'replace))
+          (user_proc temp_dir))
+        (lambda ()
+          (delete-directory/files temp_dir)))))