node: add open/close events to node and spvnode.

chain: reorganize getting tree compaction heights.

lib/blockchain/chain.js

@@ -131,6 +131,29 @@ class Chain extends AsyncEmitter {
     return this.db.close();
   }
 
+  /**
+   * Get compaction heights.
+   * @returns {Promise<Object>}
+   */
+
+  async getCompactionHeights() {
+    if (this.options.spv)
+      return null;
+
+    if (!this.options.compactTreeOnInit)
+      return null;
+
+    const {keepBlocks} = this.network.block;
+    const {compactionHeight} = await this.db.getTreeState();
+    const {compactTreeInitInterval} = this.options;
+    const compactFrom = compactionHeight + keepBlocks + compactTreeInitInterval;
+
+    return {
+      compactionHeight,
+      compactFrom
+    };
+  }
+
   /**
    * Check if we need to compact tree data.
    * @returns {Promise<Boolean>} - Should we sync
@@ -150,9 +173,7 @@ class Chain extends AsyncEmitter {
     if (this.height <= startFrom)
       return true;
 
-    const {compactionHeight} = await this.db.getTreeState();
-    const {compactTreeInitInterval} = this.options;
-    const compactFrom = compactionHeight + keepBlocks + compactTreeInitInterval;
+    const {compactFrom} = await this.getCompactionHeights();
 
     if (compactFrom > this.height) {
       this.logger.debug(

lib/node/fullnode.js

@@ -316,6 +316,7 @@ class FullNode extends Node {
     }
 
     this.logger.info('Node is loaded.');
+    this.emit('open');
   }
 
   /**
@@ -348,6 +349,7 @@ class FullNode extends Node {
 
     this.logger.info('Node is closed.');
     this.emit('closed');
+    this.emit('close');
   }
 
   /**

lib/node/spvnode.js

@@ -190,6 +190,7 @@ class SPVNode extends Node {
     await this.handleOpen();
 
     this.logger.info('Node is loaded.');
+    this.emit('open');
   }
 
   /**
@@ -218,6 +219,7 @@ class SPVNode extends Node {
 
     this.logger.info('Node is closed.');
     this.emit('closed');
+    this.emit('close');
   }
 
   /**