Allow tests to fake stdin/stdout/stderr is a console

We've been unable to effectively test cases where stdin/stdout/stderr
are consoles, because in our test cases they generally aren't. Allow the
command line flags `--fake-std{in,out,err}-is-console` to tell the CLI
to pretend that std{in,out,err} is a console.

programs/fileio.c

@@ -3010,7 +3010,7 @@ int FIO_listMultipleFiles(unsigned numFiles, const char** filenameTable, int dis
     }   }
 
     if (numFiles == 0) {
-        if (!IS_CONSOLE(stdin)) {
+        if (!UTIL_isConsole(stdin)) {
             DISPLAYLEVEL(1, "zstd: --list does not support reading from standard input \n");
         }
         DISPLAYLEVEL(1, "No files given \n");

programs/platform.h

@@ -127,6 +127,10 @@ extern "C" {
 
 /*-*********************************************
 *  Detect if isatty() and fileno() are available
+*
+*  Note: Use UTIL_isConsole() for the zstd CLI
+*  instead, as it allows faking is console for
+*  testing.
 ************************************************/
 #if (defined(__linux__) && (PLATFORM_POSIX_VERSION > 1)) \
  || (PLATFORM_POSIX_VERSION >= 200112L) \

programs/util.c

@@ -288,6 +288,34 @@ int UTIL_isLink(const char* infilename)
     return 0;
 }
 
+static int g_fakeStdinIsConsole = 0;
+static int g_fakeStderrIsConsole = 0;
+static int g_fakeStdoutIsConsole = 0;
+
+int UTIL_isConsole(FILE* file)
+{
+    if (file == stdin && g_fakeStdinIsConsole)
+        return 1;
+    if (file == stderr && g_fakeStderrIsConsole)
+        return 1;
+    if (file == stdout && g_fakeStdoutIsConsole)
+        return 1;
+    return IS_CONSOLE(file);
+}
+
+void UTIL_fakeStdinIsConsole(void)
+{
+    g_fakeStdinIsConsole = 1;
+}
+void UTIL_fakeStdoutIsConsole(void)
+{
+    g_fakeStdoutIsConsole = 1;
+}
+void UTIL_fakeStderrIsConsole(void)
+{
+    g_fakeStderrIsConsole = 1;
+}
+
 U64 UTIL_getFileSize(const char* infilename)
 {
     stat_t statbuf;

programs/util.h

@@ -175,6 +175,20 @@ int UTIL_isCompressedFile(const char* infilename, const char *extensionList[]);
 int UTIL_isLink(const char* infilename);
 int UTIL_isFIFO(const char* infilename);
 
+/**
+ * Returns with the given file descriptor is a console.
+ * Allows faking whether stdin/stdout/stderr is a console
+ * using UTIL_fake*IsConsole().
+ */
+int UTIL_isConsole(FILE* file);
+
+/**
+ * Pretends that stdin/stdout/stderr is a console for testing.
+ */
+void UTIL_fakeStdinIsConsole(void);
+void UTIL_fakeStdoutIsConsole(void);
+void UTIL_fakeStderrIsConsole(void);
+
 #define UTIL_FILESIZE_UNKNOWN  ((U64)(-1))
 U64 UTIL_getFileSize(const char* infilename);
 U64 UTIL_getTotalFileSize(const char* const * fileNamesTable, unsigned nbFiles);

programs/zstdcli.c

@@ -27,8 +27,8 @@
 /*-************************************
 *  Dependencies
 **************************************/
-#include "platform.h" /* IS_CONSOLE, PLATFORM_POSIX_VERSION */
-#include "util.h"     /* UTIL_HAS_CREATEFILELIST, UTIL_createFileList */
+#include "platform.h" /* PLATFORM_POSIX_VERSION */
+#include "util.h"     /* UTIL_HAS_CREATEFILELIST, UTIL_createFileList, UTIL_isConsole */
 #include <stdlib.h>   /* getenv */
 #include <string.h>   /* strcmp, strlen */
 #include <stdio.h>    /* fprintf(), stdin, stdout, stderr */
@@ -987,6 +987,9 @@ int main(int argCount, const char* argv[])
                 if (!strcmp(argument, "--no-progress")) { FIO_setProgressSetting(FIO_ps_never); continue; }
                 if (!strcmp(argument, "--progress")) { FIO_setProgressSetting(FIO_ps_always); continue; }
                 if (!strcmp(argument, "--exclude-compressed")) { FIO_setExcludeCompressedFile(prefs, 1); continue; }
+                if (!strcmp(argument, "--fake-stdin-is-console")) { UTIL_fakeStdinIsConsole(); continue; }
+                if (!strcmp(argument, "--fake-stdout-is-console")) { UTIL_fakeStdoutIsConsole(); continue; }
+                if (!strcmp(argument, "--fake-stderr-is-console")) { UTIL_fakeStderrIsConsole(); continue; }
 
                 /* long commands with arguments */
 #ifndef ZSTD_NODICT
@@ -1437,12 +1440,12 @@ int main(int argCount, const char* argv[])
     /* Check if input/output defined as console; trigger an error in this case */
     if (!forceStdin
      && (UTIL_searchFileNamesTable(filenames, stdinmark) != -1)
-     && IS_CONSOLE(stdin) ) {
+     && UTIL_isConsole(stdin) ) {
         DISPLAYLEVEL(1, "stdin is a console, aborting\n");
         CLEAN_RETURN(1);
     }
     if ( (!outFileName || !strcmp(outFileName, stdoutmark))
-      && IS_CONSOLE(stdout)
+      && UTIL_isConsole(stdout)
       && (UTIL_searchFileNamesTable(filenames, stdinmark) != -1)
       && !forceStdout
       && operation!=zom_decompress ) {
@@ -1479,7 +1482,7 @@ int main(int argCount, const char* argv[])
     /* No status message in pipe mode (stdin - stdout) */
     hasStdout = outFileName && !strcmp(outFileName,stdoutmark);
 
-    if ((hasStdout || !IS_CONSOLE(stderr)) && (g_displayLevel==2)) g_displayLevel=1;
+    if ((hasStdout || !UTIL_isConsole(stderr)) && (g_displayLevel==2)) g_displayLevel=1;
 
     /* IO Stream/File */
     FIO_setHasStdoutOutput(fCtx, hasStdout);