Geary.Logging: Enable API clients to suppress DEBUG logging per-domain

src/engine/api/geary-logging.vala

@@ -359,6 +359,7 @@ private unowned FileStream? stream = null;
 public void init() {
     if (init_count++ != 0)
         return;
+    Logging.suppressed_domains = new Gee.HashSet<string>();
     record_lock = GLib.Mutex();
     writer_lock = GLib.Mutex();
     max_log_length = DEFAULT_MAX_LOG_BUFFER_LENGTH;
@@ -571,12 +572,13 @@ public GLib.LogWriterOutput default_log_writer(GLib.LogLevelFlags levels,
 }
 
 private bool should_blacklist(Record record) {
+    const string DOMAIN_PREFIX = Logging.DOMAIN + ".";
     return (
-        // GdkPixbuf spams us e.g. when window focus changes,
-        // including between MainWindow and the Inspector, which is
-        // very annoying.
-        (record.levels == GLib.LogLevelFlags.LEVEL_DEBUG &&
-         record.domain == "GdkPixbuf") ||
+        // Don't need to check for the engine's domains, they were
+        // already handled by Source's methods.
+        (record.domain != Logging.DOMAIN &&
+         !record.domain.has_prefix(DOMAIN_PREFIX) &&
+         record.domain in Logging.suppressed_domains) ||
         // GAction does not support disabling parameterised actions
         // with specific values, but GTK complains if the parameter is
         // set to null to achieve the same effect, and they aren't

src/engine/util/util-logging.vala

@@ -7,6 +7,35 @@
  */
 
 
+namespace Geary.Logging {
+
+
+    internal Gee.Set<string> suppressed_domains;
+
+
+    /**
+     * Suppresses debug logging for a given logging domain.
+     *
+     * If a logging domain is suppressed, DEBUG-level logging will not
+     * be sent to the logging system.
+     *
+     * @see unsuppress_domain
+     */
+    public void suppress_domain(string domain) {
+        Logging.suppressed_domains.add(domain);
+    }
+
+    /**
+     * Un-suppresses debug logging for a given logging domain.
+     *
+     * @see suppress_domain
+     */
+    public void unsuppress_domain(string domain) {
+        Logging.suppressed_domains.remove(domain);
+    }
+
+}
+
 /**
  * Mixin interface for objects that support structured logging.
  *
@@ -167,9 +196,11 @@ public interface Geary.Logging.Source : GLib.Object {
      */
     [PrintfFormat]
     public inline void debug(string fmt, ...) {
-        log_structured(
-            this.logging_flags, LogLevelFlags.LEVEL_DEBUG, fmt, va_list()
-        );
+        if (!(this.logging_domain in Logging.suppressed_domains)) {
+            log_structured(
+                this.logging_flags, LogLevelFlags.LEVEL_DEBUG, fmt, va_list()
+            );
+        }
     }
 
     /**