error-handling: On-disk config file backend

Includes:

	- Proper error reporting when encountering syntax errors in a
	config file (file, line number, column).

	- Rewritten `config_write`, now with 99% less goto-spaghetti

	- Error state in `git_filebuf`: filebuf write functions no longer
	need to be checked for error returns. If any of the writes performed
	on a buffer fail, the last call to `git_filebuf_commit` or
	`git_filebuf_hash` will fail accordingly and set the appropiate error
	message. Baller!

1 files changed, 8 insertions, 10 deletions

diff --git a/src/posix.c b/src/posix.c
index d2364d9b4..9d96d3013 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -31,10 +31,9 @@ int p_getcwd(char *buffer_out, size_t size)
 	cwd_buffer = getcwd(buffer_out, size);
 
 	if (cwd_buffer == NULL)
-		return git__throw(GIT_EOSERR, "Failed to retrieve current working directory");
+		return -1;
 
 	git_path_mkposix(buffer_out);
-
 	git_path_string_to_dir(buffer_out, size);	//Ensure the path ends with a trailing slash
 
 	return GIT_SUCCESS;
@@ -44,14 +43,13 @@ int p_rename(const char *from, const char *to)
 {
 	if (!link(from, to)) {
 		p_unlink(from);
-		return GIT_SUCCESS;
+		return 0;
 	}
 
 	if (!rename(from, to))
-		return GIT_SUCCESS;
-
-	return GIT_ERROR;
+		return 0;
 
+	return -1;
 }
 
 #endif
@@ -64,7 +62,7 @@ int p_read(git_file fd, void *buf, size_t cnt)
 		if (r < 0) {
 			if (errno == EINTR || errno == EAGAIN)
 				continue;
-			return GIT_EOSERR;
+			return -1;
 		}
 		if (!r)
 			break;
@@ -82,14 +80,14 @@ int p_write(git_file fd, const void *buf, size_t cnt)
 		if (r < 0) {
 			if (errno == EINTR || errno == EAGAIN)
 				continue;
-			return GIT_EOSERR;
+			return -1;
 		}
 		if (!r) {
 			errno = EPIPE;
-			return GIT_EOSERR;
+			return -1;
 		}
 		cnt -= r;
 		b += r;
 	}
-	return GIT_SUCCESS;
+	return 0;
 }