patch: implement -E option

Signed-off-by: Lukas Huba <Huba.Lukas@centrum.cz>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 23 insertions, 14 deletions

diff --git a/editors/patch.c b/editors/patch.c
index 66a9474fe..fff06907f 100644
--- a/editors/patch.c
+++ b/editors/patch.c
@@ -17,7 +17,6 @@
  * -o outfile output here instead of in place
  * -r rejectfile write rejected hunks to this file
  *
- * -E remove empty files --remove-empty-files
  * -f force (no questions asked)
  * -F fuzz (number, default 2)
  * [file] which file to patch
@@ -42,7 +41,7 @@ config PATCH
           hunks to stderr, and exits with nonzero status if any hunks fail.
 
           A file compared against /dev/null (or with a date <= the epoch) is
-          created/deleted as appropriate.
+          created or deleted if -E or --remove-empty-files set.
 */
 #include "libbb.h"
 
@@ -243,15 +242,16 @@ struct globals {
 } while (0)
 
 
-#define FLAG_STR "Rup:i:Nx"
+#define FLAG_STR "Rup:i:NEx"
 /* FLAG_REVERSE must be == 1! Code uses this fact. */
 #define FLAG_REVERSE (1 << 0)
 #define FLAG_u       (1 << 1)
 #define FLAG_PATHLEN (1 << 2)
 #define FLAG_INPUT   (1 << 3)
 #define FLAG_IGNORE  (1 << 4)
+#define FLAG_RMEMPTY (1 << 5)
 //non-standard:
-#define FLAG_DEBUG   (1 << 5)
+#define FLAG_DEBUG   (1 << 6)
 
 // Dispose of a line of input, either by writing it out or discarding it.
 
@@ -551,7 +551,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
 
                         // If this is the first hunk, open the file.
                         if (TT.filein == -1) {
-                                int oldsum, newsum, del = 0;
+                                int oldsum, newsum, empty = 0;
                                 char *name;
 
                                 oldsum = TT.oldline + TT.oldlen;
@@ -564,7 +564,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
                                 if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum))
                                 {
                                         name = reverse ? newname : oldname;
-                                        del++;
+                                        empty++;
                                 }
 
                                 // handle -p path truncation.
@@ -576,10 +576,17 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
                                         }
                                 }
 
-                                if (del) {
-                                        printf("removing %s\n", name);
-                                        xunlink(name);
+                                if (empty) {
+                                        // File is empty after the patches have been applied
                                         state = 0;
+                                        if (option_mask32 & FLAG_RMEMPTY) {
+                                                // If flag -E or --remove-empty-files is set
+                                                printf("removing %s\n", name);
+                                                xunlink(name);
+                                        } else {
+                                                printf("patching file %s\n", name);
+                                                xclose(xopen(name, O_WRONLY | O_TRUNC));
+                                        }
                                 // If we've got a file to open, do so.
                                 } else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
                                         // If the old file was null, we're creating a new one.
diff --git a/include/usage.src.h b/include/usage.src.h
index 2445c1b9b..f5ddd7ba5 100644
--- a/include/usage.src.h
+++ b/include/usage.src.h
@@ -2857,17 +2857,19 @@ INSERT
        "[OPTIONS] [ORIGFILE [PATCHFILE]]"
 #define patch_full_usage "\n\n" \
         IF_LONG_OPTS( \
-       "        -p,--strip N    Strip N leading components from file names" \
-     "\n        -i,--input DIFF Read DIFF instead of stdin" \
-     "\n        -R,--reverse    Reverse patch" \
-     "\n        -N,--forward    Ignore already applied patches" \
-     "\n        --dry-run       Don't actually change files" \
+       "        -p,--strip N            Strip N leading components from file names" \
+     "\n        -i,--input DIFF         Read DIFF instead of stdin" \
+     "\n        -R,--reverse            Reverse patch" \
+     "\n        -N,--forward            Ignore already applied patches" \
+     "\n        --dry-run               Don't actually change files" \
+     "\n        -E,--remove-empty-files Remove output files if they become empty" \
         ) \
         IF_NOT_LONG_OPTS( \
        "        -p N    Strip N leading components from file names" \
      "\n        -i DIFF Read DIFF instead of stdin" \
      "\n        -R      Reverse patch" \
      "\n        -N      Ignore already applied patches" \
+     "\n        -E      Remove output files if they become empty" \
         )
 
 #define patch_example_usage \