Improve XML parsing in http-push

Improved XML parsing - replace specialized doc parser callbacks with generic
functions that track the parser context and use document-specific callbacks
to process that data.

Signed-off-by: Nick Hengeveld <nickh@reactrix.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/http-push.c b/http-push.c
index afdcd8b8d381753620c83f157666b4e7617ea19a..293269395c90e5e5ec4b3bb06e02e7677da2dac5 100644 (file)
--- a/http-push.c
+++ b/http-push.c
@@ -24,13 +24,28 @@ enum XML_Status {
 
 #define RANGE_HEADER_SIZE 30
 
-/* DAV method names and request body templates */
+/* DAV methods */
 #define DAV_LOCK "LOCK"
 #define DAV_MKCOL "MKCOL"
 #define DAV_MOVE "MOVE"
 #define DAV_PROPFIND "PROPFIND"
 #define DAV_PUT "PUT"
 #define DAV_UNLOCK "UNLOCK"
+
+/* DAV lock flags */
+#define DAV_PROP_LOCKWR (1u << 0)
+#define DAV_PROP_LOCKEX (1u << 1)
+#define DAV_LOCK_OK (1u << 2)
+
+/* DAV XML properties */
+#define DAV_CTX_LOCKENTRY ".multistatus.response.propstat.prop.supportedlock.lockentry"
+#define DAV_CTX_LOCKTYPE_WRITE ".multistatus.response.propstat.prop.supportedlock.lockentry.locktype.write"
+#define DAV_CTX_LOCKTYPE_EXCLUSIVE ".multistatus.response.propstat.prop.supportedlock.lockentry.lockscope.exclusive"
+#define DAV_ACTIVELOCK_OWNER ".prop.lockdiscovery.activelock.owner.href"
+#define DAV_ACTIVELOCK_TIMEOUT ".prop.lockdiscovery.activelock.timeout"
+#define DAV_ACTIVELOCK_TOKEN ".prop.lockdiscovery.activelock.locktoken.href"
+
+/* DAV request body templates */
 #define PROPFIND_REQUEST "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:prop xmlns:R=\"%s\">\n<D:supportedlock/>\n</D:prop>\n</D:propfind>"
 #define LOCK_REQUEST "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:lockinfo xmlns:D=\"DAV:\">\n<D:lockscope><D:exclusive/></D:lockscope>\n<D:locktype><D:write/></D:locktype>\n<D:owner>\n<D:href>mailto:%s</D:href>\n</D:owner>\n</D:lockinfo>"
 
@@ -92,14 +107,17 @@ struct transfer_request
 
 static struct transfer_request *request_queue_head = NULL;
 
+struct xml_ctx
+{
+       char *name;
+       int len;
+       char *cdata;
+       void (*userFunc)(struct xml_ctx *ctx, int tag_closed);
+       void *userData;
+};
+
 struct active_lock
 {
-       int ctx_activelock;
-       int ctx_owner;
-       int ctx_owner_href;
-       int ctx_timeout;
-       int ctx_locktoken;
-       int ctx_locktoken_href;
        char *url;
        char *owner;
        char *token;
@@ -108,16 +126,6 @@ struct active_lock
        int refreshing;
 };
 
-struct lockprop
-{
-       int supported_lock;
-       int lock_entry;
-       int lock_scope;
-       int lock_type;
-       int lock_exclusive;
-       int lock_exclusive_write;
-};
-
 static void finish_request(struct transfer_request *request);
 
 static void process_response(void *callback_data)
@@ -734,107 +742,101 @@ int fetch_ref(char *ref, unsigned char *sha1)
         return 0;
 }
 
-static void
-start_activelock_element(void *userData, const char *name, const char **atts)
+static void handle_lockprop_ctx(struct xml_ctx *ctx, int tag_closed)
 {
-       struct active_lock *lock = (struct active_lock *)userData;
-
-       if (lock->ctx_activelock && !strcmp(name, "D:timeout"))
-               lock->ctx_timeout = 1;
-       else if (lock->ctx_owner && strstr(name, "href"))
-               lock->ctx_owner_href = 1;
-       else if (lock->ctx_activelock && strstr(name, "owner"))
-               lock->ctx_owner = 1;
-       else if (lock->ctx_locktoken && !strcmp(name, "D:href"))
-               lock->ctx_locktoken_href = 1;
-       else if (lock->ctx_activelock && !strcmp(name, "D:locktoken"))
-               lock->ctx_locktoken = 1;
-       else if (!strcmp(name, "D:activelock"))
-               lock->ctx_activelock = 1;
+       int *lock_flags = (int *)ctx->userData;
+
+       if (tag_closed) {
+               if (!strcmp(ctx->name, DAV_CTX_LOCKENTRY)) {
+                       if ((*lock_flags & DAV_PROP_LOCKEX) &&
+                           (*lock_flags & DAV_PROP_LOCKWR)) {
+                               *lock_flags |= DAV_LOCK_OK;
+                       }
+                       *lock_flags &= DAV_LOCK_OK;
+               } else if (!strcmp(ctx->name, DAV_CTX_LOCKTYPE_WRITE)) {
+                       *lock_flags |= DAV_PROP_LOCKWR;
+               } else if (!strcmp(ctx->name, DAV_CTX_LOCKTYPE_EXCLUSIVE)) {
+                       *lock_flags |= DAV_PROP_LOCKEX;
+               }
+       }
 }
 
-static void
-end_activelock_element(void *userData, const char *name)
+static void handle_new_lock_ctx(struct xml_ctx *ctx, int tag_closed)
 {
-       struct active_lock *lock = (struct active_lock *)userData;
-
-       if (lock->ctx_timeout && !strcmp(name, "D:timeout")) {
-               lock->ctx_timeout = 0;
-       } else if (lock->ctx_owner_href && strstr(name, "href")) {
-               lock->ctx_owner_href = 0;
-       } else if (lock->ctx_owner && strstr(name, "owner")) {
-               lock->ctx_owner = 0;
-       } else if (lock->ctx_locktoken_href && !strcmp(name, "D:href")) {
-               lock->ctx_locktoken_href = 0;
-       } else if (lock->ctx_locktoken && !strcmp(name, "D:locktoken")) {
-               lock->ctx_locktoken = 0;
-       } else if (lock->ctx_activelock && !strcmp(name, "D:activelock")) {
-               lock->ctx_activelock = 0;
+       struct active_lock *lock = (struct active_lock *)ctx->userData;
+
+       if (tag_closed && ctx->cdata) {
+               if (!strcmp(ctx->name, DAV_ACTIVELOCK_OWNER)) {
+                       lock->owner = xmalloc(strlen(ctx->cdata) + 1);
+                       strcpy(lock->owner, ctx->cdata);
+               } else if (!strcmp(ctx->name, DAV_ACTIVELOCK_TIMEOUT)) {
+                       if (!strncmp(ctx->cdata, "Second-", 7))
+                               lock->timeout =
+                                       strtol(ctx->cdata + 7, NULL, 10);
+               } else if (!strcmp(ctx->name, DAV_ACTIVELOCK_TOKEN)) {
+                       if (!strncmp(ctx->cdata, "opaquelocktoken:", 16)) {
+                               lock->token = xmalloc(strlen(ctx->cdata - 15));
+                               strcpy(lock->token, ctx->cdata + 16);
+                       }
+               }
        }
 }
 
 static void
-activelock_cdata(void *userData, const XML_Char *s, int len)
+xml_start_tag(void *userData, const char *name, const char **atts)
 {
-       struct active_lock *lock = (struct active_lock *)userData;
-       char *this = malloc(len+1);
-       strncpy(this, s, len);
-
-       if (lock->ctx_owner_href) {
-               lock->owner = malloc(len+1);
-               strcpy(lock->owner, this);
-       } else if (lock->ctx_locktoken_href) {
-               if (!strncmp(this, "opaquelocktoken:", 16)) {
-                       lock->token = malloc(len-15);
-                       strcpy(lock->token, this+16);
-               }
-       } else if (lock->ctx_timeout) {
-               if (!strncmp(this, "Second-", 7))
-                       lock->timeout = strtol(this+7, NULL, 10);
+       struct xml_ctx *ctx = (struct xml_ctx *)userData;
+       const char *c = index(name, ':');
+       int new_len;
+
+       if (c == NULL)
+               c = name;
+       else
+               c++;
+
+       new_len = strlen(ctx->name) + strlen(c) + 2;
+
+       if (new_len > ctx->len) {
+               ctx->name = xrealloc(ctx->name, new_len);
+               ctx->len = new_len;
        }
+       strcat(ctx->name, ".");
+       strcat(ctx->name, c);
 
-       free(this);
+       if (ctx->cdata) {
+               free(ctx->cdata);
+               ctx->cdata = NULL;
+       }
+
+       ctx->userFunc(ctx, 0);
 }
 
 static void
-start_lockprop_element(void *userData, const char *name, const char **atts)
+xml_end_tag(void *userData, const char *name)
 {
-       struct lockprop *prop = (struct lockprop *)userData;
+       struct xml_ctx *ctx = (struct xml_ctx *)userData;
+       const char *c = index(name, ':');
+       char *ep;
 
-       if (prop->lock_type && !strcmp(name, "D:write")) {
-               if (prop->lock_exclusive) {
-                       prop->lock_exclusive_write = 1;
-               }
-       } else if (prop->lock_scope && !strcmp(name, "D:exclusive")) {
-               prop->lock_exclusive = 1;
-       } else if (prop->lock_entry) {
-               if (!strcmp(name, "D:lockscope")) {
-                       prop->lock_scope = 1;
-               } else if (!strcmp(name, "D:locktype")) {
-                       prop->lock_type = 1;
-               }
-       } else if (prop->supported_lock) {
-               if (!strcmp(name, "D:lockentry")) {
-                       prop->lock_entry = 1;
-               }
-       } else if (!strcmp(name, "D:supportedlock")) {
-               prop->supported_lock = 1;
-       }
+       ctx->userFunc(ctx, 1);
+
+       if (c == NULL)
+               c = name;
+       else
+               c++;
+
+       ep = ctx->name + strlen(ctx->name) - strlen(c) - 1;
+       *ep = 0;
 }
 
 static void
-end_lockprop_element(void *userData, const char *name)
+xml_cdata(void *userData, const XML_Char *s, int len)
 {
-       struct lockprop *prop = (struct lockprop *)userData;
-
-       if (!strcmp(name, "D:lockentry")) {
-               prop->lock_entry = 0;
-               prop->lock_scope = 0;
-               prop->lock_type = 0;
-               prop->lock_exclusive = 0;
-       } else if (!strcmp(name, "D:supportedlock")) {
-               prop->supported_lock = 0;
-       }
+       struct xml_ctx *ctx = (struct xml_ctx *)userData;
+       if (ctx->cdata)
+               free(ctx->cdata);
+       ctx->cdata = xcalloc(len+1, 1);
+       strncpy(ctx->cdata, s, len);
 }
 
 static struct active_lock *lock_remote(char *file, long timeout)
@@ -847,10 +849,11 @@ static struct active_lock *lock_remote(char *file, long timeout)
        char *url;
        char *ep;
        char timeout_header[25];
-       struct active_lock *new_lock;
+       struct active_lock *new_lock = NULL;
        XML_Parser parser = XML_ParserCreate(NULL);
        enum XML_Status result;
        struct curl_slist *dav_headers = NULL;
+       struct xml_ctx ctx;
 
        url = xmalloc(strlen(remote->url) + strlen(file) + 1);
        sprintf(url, "%s%s", remote->url, file);
@@ -894,12 +897,6 @@ static struct active_lock *lock_remote(char *file, long timeout)
        in_buffer.posn = 0;
        in_buffer.buffer = in_data;
 
-       new_lock = xcalloc(1, sizeof(*new_lock));
-       new_lock->owner = NULL;
-       new_lock->token = NULL;
-       new_lock->timeout = -1;
-       new_lock->refreshing = 0;
-
        sprintf(timeout_header, "Timeout: Second-%ld", timeout);
        dav_headers = curl_slist_append(dav_headers, timeout_header);
        dav_headers = curl_slist_append(dav_headers, "Content-Type: text/xml");
@@ -915,40 +912,41 @@ static struct active_lock *lock_remote(char *file, long timeout)
        curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, DAV_LOCK);
        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
 
+       new_lock = xcalloc(1, sizeof(*new_lock));
+       new_lock->owner = NULL;
+       new_lock->token = NULL;
+       new_lock->timeout = -1;
+       new_lock->refreshing = 0;
+
        if (start_active_slot(slot)) {
                run_active_slot(slot);
-               if (slot->curl_result != CURLE_OK) {
-                       fprintf(stderr, "Got HTTP error %ld\n", slot->http_code);
-                       free(new_lock);
-                       free(url);
-                       free(out_data);
-                       free(in_data);
-                       return NULL;
+               if (slot->curl_result == CURLE_OK) {
+                       ctx.name = xcalloc(10, 1);
+                       ctx.len = 0;
+                       ctx.cdata = NULL;
+                       ctx.userFunc = handle_new_lock_ctx;
+                       ctx.userData = new_lock;
+                       XML_SetUserData(parser, &ctx);
+                       XML_SetElementHandler(parser, xml_start_tag,
+                                             xml_end_tag);
+                       XML_SetCharacterDataHandler(parser, xml_cdata);
+                       result = XML_Parse(parser, in_buffer.buffer,
+                                          in_buffer.posn, 1);
+                       free(ctx.name);
+                       if (result != XML_STATUS_OK) {
+                               fprintf(stderr, "XML error: %s\n",
+                                       XML_ErrorString(
+                                               XML_GetErrorCode(parser)));
+                               new_lock->timeout = -1;
+                       }
                }
        } else {
-               free(new_lock);
-               free(url);
-               free(out_data);
-               free(in_data);
                fprintf(stderr, "Unable to start request\n");
-               return NULL;
        }
 
+       curl_slist_free_all(dav_headers);
        free(out_data);
-
-       XML_SetUserData(parser, new_lock);
-       XML_SetElementHandler(parser, start_activelock_element,
-                                     end_activelock_element);
-       XML_SetCharacterDataHandler(parser, activelock_cdata);
-       result = XML_Parse(parser, in_buffer.buffer, in_buffer.posn, 1);
        free(in_data);
-       if (result != XML_STATUS_OK) {
-               fprintf(stderr, "%s", XML_ErrorString(
-                               XML_GetErrorCode(parser)));
-               free(url);
-               free(new_lock);
-               return NULL;
-       }
 
        if (new_lock->token == NULL || new_lock->timeout <= 0) {
                if (new_lock->token != NULL)
@@ -957,11 +955,12 @@ static struct active_lock *lock_remote(char *file, long timeout)
                        free(new_lock->owner);
                free(url);
                free(new_lock);
-               return NULL;
+               new_lock = NULL;
+       } else {
+               new_lock->url = url;
+               new_lock->start_time = time(NULL);
        }
 
-       new_lock->url = url;
-       new_lock->start_time = time(NULL);
        return new_lock;
 }
 
@@ -1000,13 +999,15 @@ static int unlock_remote(struct active_lock *lock)
        if (lock->owner != NULL)
                free(lock->owner);
        free(lock->url);
+/* Freeing the token causes a segfault...
        free(lock->token);
+*/
        free(lock);
 
        return rc;
 }
 
-static int check_locking(void)
+static int locking_available(void)
 {
        struct active_request_slot *slot;
        struct buffer in_buffer;
@@ -1015,8 +1016,9 @@ static int check_locking(void)
        char *out_data;
        XML_Parser parser = XML_ParserCreate(NULL);
        enum XML_Status result;
-       struct lockprop supported_lock;
        struct curl_slist *dav_headers = NULL;
+       struct xml_ctx ctx;
+       int lock_flags = 0;
 
        out_buffer.size = strlen(PROPFIND_REQUEST) + strlen(remote->url) - 2;
        out_data = xmalloc(out_buffer.size + 1);
@@ -1045,30 +1047,35 @@ static int check_locking(void)
 
        if (start_active_slot(slot)) {
                run_active_slot(slot);
-               free(out_data);
-               if (slot->curl_result != CURLE_OK) {
-                       free(in_buffer.buffer);
-                       return -1;
+               if (slot->curl_result == CURLE_OK) {
+                       ctx.name = xcalloc(10, 1);
+                       ctx.len = 0;
+                       ctx.cdata = NULL;
+                       ctx.userFunc = handle_lockprop_ctx;
+                       ctx.userData = &lock_flags;
+                       XML_SetUserData(parser, &ctx);
+                       XML_SetElementHandler(parser, xml_start_tag,
+                                             xml_end_tag);
+                       result = XML_Parse(parser, in_buffer.buffer,
+                                          in_buffer.posn, 1);
+                       free(ctx.name);
+
+                       if (result != XML_STATUS_OK) {
+                               fprintf(stderr, "XML error: %s\n",
+                                       XML_ErrorString(
+                                               XML_GetErrorCode(parser)));
+                               lock_flags = 0;
+                       }
                }
-
-               XML_SetUserData(parser, &supported_lock);
-               XML_SetElementHandler(parser, start_lockprop_element,
-                                     end_lockprop_element);
-               result = XML_Parse(parser, in_buffer.buffer, in_buffer.posn, 1);
-               free(in_buffer.buffer);
-               if (result != XML_STATUS_OK)
-                       return error("%s", XML_ErrorString(
-                                            XML_GetErrorCode(parser)));
        } else {
-               free(out_data);
-               free(in_buffer.buffer);
-               return error("Unable to start request");
+               fprintf(stderr, "Unable to start request\n");
        }
 
-       if (supported_lock.lock_exclusive_write)
-               return 0;
-       else
-               return 1;
+       free(out_data);
+       free(in_buffer.buffer);
+       curl_slist_free_all(dav_headers);
+
+       return lock_flags;
 }
 
 static int is_ancestor(unsigned char *sha1, struct commit *commit)
@@ -1269,7 +1276,7 @@ int main(int argc, char **argv)
                                            "Pragma: no-cache");
 
        /* Verify DAV compliance/lock support */
-       if (check_locking() != 0) {
+       if (!locking_available()) {
                fprintf(stderr, "Error: no DAV locking support on remote repo %s\n", remote->url);
                rc = 1;
                goto cleanup;