[PATCH] http: make curl callbacks match contracts from curl header

[Dan McGee <dpmcgee@gmail.com>]

Yes, these don't match perfectly with the void* first parameter of the
fread/fwrite in the standard library, but they do match the curl
expected method signature. This is needed when a refactor passes a
curl_write_callback around, which would otherwise give incorrect
parameter warnings.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
---

Cast the const-ness away in process_alternates_response with the call to
fwrite_buffer() as suggested by Junio, which shows the correct intent rather
than making the variable non-const to begin with. The static modifier was still
dropped.

 http-walker.c |    4 ++--
 http.c        |   12 ++++++------
 http.h        |    6 +++---
 remote-curl.c |    2 +-
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/http-walker.c b/http-walker.c
index 9bc8114..51a906e 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -185,7 +185,7 @@ static void process_alternates_response(void *callback_data)
 	struct active_request_slot *slot = alt_req->slot;
 	struct alt_base *tail = cdata->alt;
 	const char *base = alt_req->base;
-	static const char null_byte = '\0';
+	const char null_byte = '\0';
 	char *data;
 	int i = 0;
 
@@ -218,7 +218,7 @@ static void process_alternates_response(void *callback_data)
 		}
 	}
 
-	fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
+	fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 	alt_req->buffer->len--;
 	data = alt_req->buffer->buf;
 
diff --git a/http.c b/http.c
index 9e76772..f44816b 100644
--- a/http.c
+++ b/http.c
@@ -60,7 +60,7 @@ static struct curl_slist *no_pragma_header;
 
 static struct active_request_slot *active_queue_head;
 
-size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
 	size_t size = eltsize * nmemb;
 	struct buffer *buffer = buffer_;
@@ -92,7 +92,7 @@ curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
 }
 #endif
 
-size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
 	size_t size = eltsize * nmemb;
 	struct strbuf *buffer = buffer_;
@@ -102,7 +102,7 @@ size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer
 	return size;
 }
 
-size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf)
+size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf)
 {
 	data_received++;
 	return eltsize * nmemb;
@@ -1166,7 +1166,7 @@ abort:
 }
 
 /* Helpers for fetching objects (loose) */
-static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
+static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
 			       void *data)
 {
 	unsigned char expn[4096];
@@ -1183,7 +1183,7 @@ static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 	} while (posn < size);
 
 	freq->stream.avail_in = size;
-	freq->stream.next_in = ptr;
+	freq->stream.next_in = (void *)ptr;
 	do {
 		freq->stream.next_out = expn;
 		freq->stream.avail_out = sizeof(expn);
@@ -1202,7 +1202,7 @@ struct http_object_request *new_http_object_request(const char *base_url,
 	char *filename;
 	char prevfile[PATH_MAX];
 	int prevlocal;
-	unsigned char prev_buf[PREV_BUF_SIZE];
+	char prev_buf[PREV_BUF_SIZE];
 	ssize_t prev_read = 0;
 	long prev_posn = 0;
 	char range[RANGE_HEADER_SIZE];
diff --git a/http.h b/http.h
index e9ed3c2..19b7134 100644
--- a/http.h
+++ b/http.h
@@ -66,9 +66,9 @@ struct buffer {
 };
 
 /* Curl request read/write callbacks */
-extern size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
-extern size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
-extern size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
+extern size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
+extern size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
+extern size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
 #ifndef NO_CURL_IOCTL
 extern curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp);
 #endif
diff --git a/remote-curl.c b/remote-curl.c
index 775d614..17d8a9b 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -347,7 +347,7 @@ static curlioerr rpc_ioctl(CURL *handle, int cmd, void *clientp)
 }
 #endif
 
-static size_t rpc_in(const void *ptr, size_t eltsize,
+static size_t rpc_in(char *ptr, size_t eltsize,
 		size_t nmemb, void *buffer_)
 {
 	size_t size = eltsize * nmemb;
-- 
1.7.4.2