Merge branch 'hv/mingw-fs-funnies'

* hv/mingw-fs-funnies:
  mingw_rmdir: set errno=ENOTEMPTY when appropriate
  mingw: add fallback for rmdir in case directory is in use
  mingw: make failures to unlink or move raise a question
  mingw: work around irregular failures of unlink on windows
  mingw: move unlink wrapper to mingw.c

2 files changed, 173 insertions, 9 deletions

diff --git a/compat/mingw.c b/compat/mingw.c
index bee6054419..878b1de97c 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2,6 +2,9 @@
 #include "win32.h"
 #include <conio.h>
 #include "../strbuf.h"
+#include "../run-command.h"
+
+static const int delay[] = { 0, 1, 10, 20, 40 };
 
 int err_win_to_posix(DWORD winerr)
 {
@@ -116,6 +119,165 @@ int err_win_to_posix(DWORD winerr)
 	return error;
 }
 
+static inline int is_file_in_use_error(DWORD errcode)
+{
+	switch (errcode) {
+	case ERROR_SHARING_VIOLATION:
+	case ERROR_ACCESS_DENIED:
+		return 1;
+	}
+
+	return 0;
+}
+
+static int read_yes_no_answer(void)
+{
+	char answer[1024];
+
+	if (fgets(answer, sizeof(answer), stdin)) {
+		size_t answer_len = strlen(answer);
+		int got_full_line = 0, c;
+
+		/* remove the newline */
+		if (answer_len >= 2 && answer[answer_len-2] == '\r') {
+			answer[answer_len-2] = '\0';
+			got_full_line = 1;
+		} else if (answer_len >= 1 && answer[answer_len-1] == '\n') {
+			answer[answer_len-1] = '\0';
+			got_full_line = 1;
+		}
+		/* flush the buffer in case we did not get the full line */
+		if (!got_full_line)
+			while ((c = getchar()) != EOF && c != '\n')
+				;
+	} else
+		/* we could not read, return the
+		 * default answer which is no */
+		return 0;
+
+	if (tolower(answer[0]) == 'y' && !answer[1])
+		return 1;
+	if (!strncasecmp(answer, "yes", sizeof(answer)))
+		return 1;
+	if (tolower(answer[0]) == 'n' && !answer[1])
+		return 0;
+	if (!strncasecmp(answer, "no", sizeof(answer)))
+		return 0;
+
+	/* did not find an answer we understand */
+	return -1;
+}
+
+static int ask_yes_no_if_possible(const char *format, ...)
+{
+	char question[4096];
+	const char *retry_hook[] = { NULL, NULL, NULL };
+	va_list args;
+
+	va_start(args, format);
+	vsnprintf(question, sizeof(question), format, args);
+	va_end(args);
+
+	if ((retry_hook[0] = getenv("GIT_ASK_YESNO"))) {
+		retry_hook[1] = question;
+		return !run_command_v_opt(retry_hook, 0);
+	}
+
+	if (!isatty(_fileno(stdin)) || !isatty(_fileno(stderr)))
+		return 0;
+
+	while (1) {
+		int answer;
+		fprintf(stderr, "%s (y/n) ", question);
+
+		if ((answer = read_yes_no_answer()) >= 0)
+			return answer;
+
+		fprintf(stderr, "Sorry, I did not understand your answer. "
+				"Please type 'y' or 'n'\n");
+	}
+}
+
+#undef unlink
+int mingw_unlink(const char *pathname)
+{
+	int ret, tries = 0;
+
+	/* read-only files cannot be removed */
+	chmod(pathname, 0666);
+	while ((ret = unlink(pathname)) == -1 && tries < ARRAY_SIZE(delay)) {
+		if (!is_file_in_use_error(GetLastError()))
+			break;
+		/*
+		 * We assume that some other process had the source or
+		 * destination file open at the wrong moment and retry.
+		 * In order to give the other process a higher chance to
+		 * complete its operation, we give up our time slice now.
+		 * If we have to retry again, we do sleep a bit.
+		 */
+		Sleep(delay[tries]);
+		tries++;
+	}
+	while (ret == -1 && is_file_in_use_error(GetLastError()) &&
+	       ask_yes_no_if_possible("Unlink of file '%s' failed. "
+			"Should I try again?", pathname))
+	       ret = unlink(pathname);
+	return ret;
+}
+
+static int is_dir_empty(const char *path)
+{
+	struct strbuf buf = STRBUF_INIT;
+	WIN32_FIND_DATAA findbuf;
+	HANDLE handle;
+
+	strbuf_addf(&buf, "%s\\*", path);
+	handle = FindFirstFileA(buf.buf, &findbuf);
+	if (handle == INVALID_HANDLE_VALUE) {
+		strbuf_release(&buf);
+		return GetLastError() == ERROR_NO_MORE_FILES;
+	}
+
+	while (!strcmp(findbuf.cFileName, ".") ||
+			!strcmp(findbuf.cFileName, ".."))
+		if (!FindNextFile(handle, &findbuf)) {
+			strbuf_release(&buf);
+			return GetLastError() == ERROR_NO_MORE_FILES;
+		}
+	FindClose(handle);
+	strbuf_release(&buf);
+	return 0;
+}
+
+#undef rmdir
+int mingw_rmdir(const char *pathname)
+{
+	int ret, tries = 0;
+
+	while ((ret = rmdir(pathname)) == -1 && tries < ARRAY_SIZE(delay)) {
+		if (!is_file_in_use_error(GetLastError()))
+			break;
+		if (!is_dir_empty(pathname)) {
+			errno = ENOTEMPTY;
+			break;
+		}
+		/*
+		 * We assume that some other process had the source or
+		 * destination file open at the wrong moment and retry.
+		 * In order to give the other process a higher chance to
+		 * complete its operation, we give up our time slice now.
+		 * If we have to retry again, we do sleep a bit.
+		 */
+		Sleep(delay[tries]);
+		tries++;
+	}
+	while (ret == -1 && is_file_in_use_error(GetLastError()) &&
+	       ask_yes_no_if_possible("Deletion of directory '%s' failed. "
+			"Should I try again?", pathname))
+	       ret = rmdir(pathname);
+	return ret;
+}
+
 #undef open
 int mingw_open (const char *filename, int oflags, ...)
 {
@@ -1249,7 +1411,6 @@ int mingw_rename(const char *pold, const char *pnew)
 {
 	DWORD attrs, gle;
 	int tries = 0;
-	static const int delay[] = { 0, 1, 10, 20, 40 };
 
 	/*
 	 * Try native rename() first to get errno right.
@@ -1291,6 +1452,11 @@ repeat:
 		tries++;
 		goto repeat;
 	}
+	if (gle == ERROR_ACCESS_DENIED &&
+	       ask_yes_no_if_possible("Rename from '%s' to '%s' failed. "
+		       "Should I try again?", pold, pnew))
+		goto repeat;
+
 	errno = EACCES;
 	return -1;
 }
diff --git a/compat/mingw.h b/compat/mingw.h
index cafc1eb08a..fe6ba34043 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -119,14 +119,6 @@ static inline int mingw_mkdir(const char *path, int mode)
 }
 #define mkdir mingw_mkdir
 
-static inline int mingw_unlink(const char *pathname)
-{
-	/* read-only files cannot be removed */
-	chmod(pathname, 0666);
-	return unlink(pathname);
-}
-#define unlink mingw_unlink
-
 #define WNOHANG 1
 pid_t waitpid(pid_t pid, int *status, unsigned options);
 
@@ -174,6 +166,12 @@ int link(const char *oldpath, const char *newpath);
  * replacements of existing functions
  */
 
+int mingw_unlink(const char *pathname);
+#define unlink mingw_unlink
+
+int mingw_rmdir(const char *path);
+#define rmdir mingw_rmdir
+
 int mingw_open (const char *filename, int oflags, ...);
 #define open mingw_open