modularized all source code (#4391)

* modularized all external plugins

* added README.md in plugins

* fixed title

* fixed typo

* relative link to external plugins

* external plugins configuration README

* added plugins link

* remove plugins link

* plugin names are links

* added links to external plugins

* removed unecessary spacing

* list to table

* added language

* fixed typo

* list to table on internal plugins

* added more documentation to internal plugins

* moved python, node, and bash code and configs into the external plugins

* added statsd README

* fix bug with corrupting config.h every 2nd compilation

* moved all config files together with their code

* more documentation

* diskspace info

* fixed broken links in apps.plugin

* added backends docs

* updated plugins readme

* move nc-backend.sh to backends

* created daemon directory

* moved all code outside src/

* fixed readme identation

* renamed plugins.d.plugin to plugins.d

* updated readme

* removed linux- from linux plugins

* updated readme

* updated readme

* updated readme

* updated readme

* updated readme

* updated readme

* fixed README.md links

* fixed netdata tree links

* updated codacy, codeclimate and lgtm excluded paths

* update CMakeLists.txt

* updated automake options at top directory

* libnetdata slit into directories

* updated READMEs

* updated READMEs

* updated ARL docs

* updated ARL docs

* moved /plugins to /collectors

* moved all external plugins outside plugins.d

* updated codacy, codeclimate, lgtm

* updated README

* updated url

* updated readme

* updated readme

* updated readme

* updated readme

* moved api and web into webserver

* web/api web/gui web/server

* modularized webserver

* removed web/gui/version.txt

1 files changed, 88 insertions, 0 deletions

diff --git a/registry/registry_url.c b/registry/registry_url.c
new file mode 100644
index 0000000000..6a71064588
--- /dev/null
+++ b/registry/registry_url.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../daemon/common.h"
+#include "registry_internals.h"
+
+// ----------------------------------------------------------------------------
+// REGISTRY_URL
+
+int registry_url_compare(void *a, void *b) {
+    if(((REGISTRY_URL *)a)->hash < ((REGISTRY_URL *)b)->hash) return -1;
+    else if(((REGISTRY_URL *)a)->hash > ((REGISTRY_URL *)b)->hash) return 1;
+    else return strcmp(((REGISTRY_URL *)a)->url, ((REGISTRY_URL *)b)->url);
+}
+
+inline REGISTRY_URL *registry_url_index_add(REGISTRY_URL *u) {
+    return (REGISTRY_URL *)avl_insert(&(registry.registry_urls_root_index), (avl *)(u));
+}
+
+inline REGISTRY_URL *registry_url_index_del(REGISTRY_URL *u) {
+    return (REGISTRY_URL *)avl_remove(&(registry.registry_urls_root_index), (avl *)(u));
+}
+
+REGISTRY_URL *registry_url_get(const char *url, size_t urllen) {
+    // protection from too big URLs
+    if(urllen > registry.max_url_length)
+        urllen = registry.max_url_length;
+
+    debug(D_REGISTRY, "Registry: registry_url_get('%s', %zu)", url, urllen);
+
+    char buf[sizeof(REGISTRY_URL) + urllen]; // no need for +1, 1 is already in REGISTRY_URL
+    REGISTRY_URL *n = (REGISTRY_URL *)&buf[0];
+    n->len = (uint16_t)urllen;
+    strncpyz(n->url, url, n->len);
+    n->hash = simple_hash(n->url);
+
+    REGISTRY_URL *u = (REGISTRY_URL *)avl_search(&(registry.registry_urls_root_index), (avl *)n);
+    if(!u) {
+        debug(D_REGISTRY, "Registry: registry_url_get('%s', %zu): allocating %zu bytes", url, urllen, sizeof(REGISTRY_URL) + urllen);
+        u = callocz(1, sizeof(REGISTRY_URL) + urllen); // no need for +1, 1 is already in REGISTRY_URL
+
+        // a simple strcpy() should do the job
+        // but I prefer to be safe, since the caller specified urllen
+        u->len = (uint16_t)urllen;
+        strncpyz(u->url, url, u->len);
+        u->links = 0;
+        u->hash = simple_hash(u->url);
+
+        registry.urls_memory += sizeof(REGISTRY_URL) + urllen; // no need for +1, 1 is already in REGISTRY_URL
+
+        debug(D_REGISTRY, "Registry: registry_url_get('%s'): indexing it", url);
+        n = registry_url_index_add(u);
+        if(n != u) {
+            error("INTERNAL ERROR: registry_url_get(): url '%s' already exists in the registry as '%s'", u->url, n->url);
+            free(u);
+            u = n;
+        }
+        else
+            registry.urls_count++;
+    }
+
+    return u;
+}
+
+void registry_url_link(REGISTRY_URL *u) {
+    u->links++;
+    debug(D_REGISTRY, "Registry: registry_url_link('%s'): URL has now %u links", u->url, u->links);
+}
+
+void registry_url_unlink(REGISTRY_URL *u) {
+    u->links--;
+    if(!u->links) {
+        debug(D_REGISTRY, "Registry: registry_url_unlink('%s'): No more links for this URL", u->url);
+        REGISTRY_URL *n = registry_url_index_del(u);
+        if(!n) {
+            error("INTERNAL ERROR: registry_url_unlink('%s'): cannot find url in index", u->url);
+        }
+        else {
+            if(n != u) {
+                error("INTERNAL ERROR: registry_url_unlink('%s'): deleted different url '%s'", u->url, n->url);
+            }
+
+            registry.urls_memory -= sizeof(REGISTRY_URL) + n->len; // no need for +1, 1 is already in REGISTRY_URL
+            freez(n);
+        }
+    }
+    else
+        debug(D_REGISTRY, "Registry: registry_url_unlink('%s'): URL has %u links left", u->url, u->links);
+}