Merge pull request #2279 from senhuang42/show_warnings_with_multiple_input_files

Add a warning whenever (de)compressing multiple files

programs/fileio.c

@@ -619,17 +619,10 @@ FIO_openDstFile(FIO_prefs_t* const prefs,
                             dstFileName);
                     return NULL;
                 }
-                DISPLAY("zstd: %s already exists; overwrite (y/N) ? ",
+                DISPLAY("zstd: %s already exists; ", dstFileName);
-                        dstFileName);
+                if (UTIL_requireUserConfirmation("overwrite (y/n) ? ", "Not overwritten  \n", "yY"))
-                {   int ch = getchar();
-                    if ((ch!='Y') && (ch!='y')) {
-                        DISPLAY("    not overwritten  \n");
-                        /* flush rest of input line */
-                        while ((ch!=EOF) && (ch!='\n')) ch = getchar();
                     return NULL;
             }
-                    while ((ch!=EOF) && (ch!='\n')) ch = getchar();
-            }   }
             /* need to unlink */
             FIO_removeFile(dstFileName);
     }   }
@@ -796,6 +789,42 @@ static void FIO_adjustMemLimitForPatchFromMode(FIO_prefs_t* const prefs,
     FIO_setMemLimit(prefs, (unsigned)maxSize);
 }
 
+/* FIO_removeMultiFilesWarning() :
+ * Returns 1 if the console should abort, 0 if console should proceed.
+ * This function handles logic when processing multiple files with -o, displaying the appropriate warnings/prompts.
+ * 
+ * If -f is specified, or there is just 1 file, zstd will always proceed as usual.
+ * If --rm is specified, there will be a prompt asking for user confirmation.
+ *         If -f is specified with --rm, zstd will proceed as usual
+ *         If -q is specified with --rm, zstd will abort pre-emptively
+ *         If neither flag is specified, zstd will prompt the user for confirmation to proceed.
+ * If --rm is not specified, then zstd will print a warning to the user (which can be silenced with -q).
+ */
+static int FIO_removeMultiFilesWarning(const FIO_prefs_t* const prefs, int displayLevelCutoff, const char* outFileName)
+{
+    int error = 0;
+    if (prefs->nbFiles > 1 && !prefs->overwrite) {
+        if (g_display_prefs.displayLevel <= displayLevelCutoff) {
+            if (prefs->removeSrcFile) {
+                DISPLAYLEVEL(1, "zstd: Aborting... not deleting files and processing into dst: %s", outFileName);
+                error =  1;
+            }
+        } else {
+            if (!strcmp(outFileName, stdoutmark)) {
+                DISPLAYLEVEL(2, "zstd: WARNING: all input files will be processed and concatenated into stdout. ");
+            } else {
+                DISPLAYLEVEL(2, "zstd: WARNING: all input files will be processed and concatenated into a single output file: %s ", outFileName);
+            }
+            DISPLAYLEVEL(2, "\nThe concatenated output CANNOT regenerate the original directory tree. ")
+            if (prefs->removeSrcFile) {
+                error = g_display_prefs.displayLevel > displayLevelCutoff && UTIL_requireUserConfirmation("This is a destructive operation. Proceed? (y/n): ", "Aborting...", "yY");
+            }
+        }
+        DISPLAY("\n");
+    }
+    return error;
+}
+
 #ifndef ZSTD_NOCOMPRESS
 
 /* **********************************************************************
@@ -1700,6 +1729,10 @@ int FIO_compressMultipleFilenames(FIO_prefs_t* const prefs,
     /* init */
     assert(outFileName != NULL || suffix != NULL);
     if (outFileName != NULL) {   /* output into a single destination (stdout typically) */
+        if (FIO_removeMultiFilesWarning(prefs, 1 /* displayLevelCutoff */, outFileName)) {
+            FIO_freeCResources(ress);
+            return 1;
+        }
         ress.dstFile = FIO_openDstFile(prefs, NULL, outFileName);
         if (ress.dstFile == NULL) {  /* could not open outFileName */
             error = 1;
@@ -2594,6 +2627,10 @@ FIO_decompressMultipleFilenames(FIO_prefs_t* const prefs,
     dRess_t ress = FIO_createDResources(prefs, dictFileName);
 
     if (outFileName) {
+        if (FIO_removeMultiFilesWarning(prefs, 1 /* displayLevelCutoff */, outFileName)) {
+            FIO_freeDResources(ress);
+            return 1;
+        }
         if (!prefs->testMode) {
             ress.dstFile = FIO_openDstFile(prefs, NULL, outFileName);
             if (ress.dstFile == 0) EXM_THROW(19, "cannot open %s", outFileName);

programs/util.c

@@ -87,6 +87,22 @@ UTIL_STATIC void* UTIL_realloc(void *ptr, size_t size)
 ******************************************/
 int g_utilDisplayLevel;
 
+int UTIL_requireUserConfirmation(const char* prompt, const char* abortMsg,
+                                          const char* acceptableLetters) {
+    int ch, result;
+    UTIL_DISPLAY("%s", prompt);
+    ch = getchar();
+    result = 0;
+    if (strchr(acceptableLetters, ch) == NULL) {
+        UTIL_DISPLAY("%s", abortMsg);
+        result = 1;
+    }
+    /* flush the rest */
+    while ((ch!=EOF) && (ch!='\n'))
+        ch = getchar();
+    return result;
+}
+
 
 /*-*************************************
 *  Constants

programs/util.h

@@ -93,6 +93,12 @@ extern "C" {
 ******************************************/
 extern int g_utilDisplayLevel;
 
+/**
+ * Displays a message prompt and returns success (0) if first character from stdin
+ * matches any from acceptableLetters. Otherwise, returns failure (1) and displays abortMsg.
+ */
+int UTIL_requireUserConfirmation(const char* prompt, const char* abortMsg, const char* acceptableLetters);
+
 
 /*-****************************************
 *  File functions

programs/zstd.1.md

@@ -213,7 +213,8 @@ the last one takes effect.
     and disabled when output is stdout.
     This setting overrides default and can force sparse mode over stdout.
 * `--rm`:
-    remove source file(s) after successful compression or decompression
+    remove source file(s) after successful compression or decompression. If used in combination with
+    -o, will trigger a confirmation prompt (which can be silenced with -f), as this is a destructive operation. 
 * `-k`, `--keep`:
     keep source file(s) after successful compression or decompression.
     This is the default behavior.

tests/playTests.sh

@@ -369,6 +369,22 @@ zstd -d tmp1.zst tmp2.zst -o tmp
 touch tmpexists
 zstd tmp1 tmp2 -f -o tmpexists
 zstd tmp1 tmp2 -q -o tmpexists && die "should have refused to overwrite"
+println gooder > tmp_rm1
+println boi > tmp_rm2
+println worldly > tmp_rm3
+echo 'y' | zstd tmp_rm1 tmp_rm2 -o tmp_rm3.zst --rm     # tests the warning prompt for --rm with multiple inputs into once source
+test ! -f tmp_rm1
+test ! -f tmp_rm2
+cp tmp_rm3.zst tmp_rm4.zst
+echo 'Y' | zstd -d tmp_rm3.zst tmp_rm4.zst -o tmp_rm_out --rm
+test ! -f tmp_rm3.zst
+test ! -f tmp_rm4.zst
+echo 'yes' | zstd tmp_rm_out tmp_rm3 -c --rm
+test ! -f tmp_rm_out
+test ! -f tmp_rm3
+println gooder > tmpexists1
+zstd tmpexists1 tmpexists -c --rm -f
+
 # Bug: PR #972
 if [ "$?" -eq 139 ]; then
   die "should not have segfaulted"