xterm

[VSoRC/.git] / node_modules / xterm / src / browser / renderer / atlas / CharAtlasCache.ts

diff --git a/node_modules/xterm/src/browser/renderer/atlas/CharAtlasCache.ts b/node_modules/xterm/src/browser/renderer/atlas/CharAtlasCache.ts
new file mode 100644 (file)
index 0000000..257835b
--- /dev/null
+++ b/node_modules/xterm/src/browser/renderer/atlas/CharAtlasCache.ts
@@ -0,0 +1,95 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { generateConfig, configEquals } from 'browser/renderer/atlas/CharAtlasUtils';
+import { BaseCharAtlas } from 'browser/renderer/atlas/BaseCharAtlas';
+import { DynamicCharAtlas } from 'browser/renderer/atlas/DynamicCharAtlas';
+import { ICharAtlasConfig } from 'browser/renderer/atlas/Types';
+import { IColorSet } from 'browser/Types';
+import { ITerminalOptions } from 'common/services/Services';
+
+interface ICharAtlasCacheEntry {
+  atlas: BaseCharAtlas;
+  config: ICharAtlasConfig;
+  // N.B. This implementation potentially holds onto copies of the terminal forever, so
+  // this may cause memory leaks.
+  ownedBy: number[];
+}
+
+const charAtlasCache: ICharAtlasCacheEntry[] = [];
+
+/**
+ * Acquires a char atlas, either generating a new one or returning an existing
+ * one that is in use by another terminal.
+ */
+export function acquireCharAtlas(
+  options: ITerminalOptions,
+  rendererId: number,
+  colors: IColorSet,
+  scaledCharWidth: number,
+  scaledCharHeight: number
+): BaseCharAtlas {
+  const newConfig = generateConfig(scaledCharWidth, scaledCharHeight, options, colors);
+
+  // Check to see if the renderer already owns this config
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const entry = charAtlasCache[i];
+    const ownedByIndex = entry.ownedBy.indexOf(rendererId);
+    if (ownedByIndex >= 0) {
+      if (configEquals(entry.config, newConfig)) {
+        return entry.atlas;
+      }
+      // The configs differ, release the renderer from the entry
+      if (entry.ownedBy.length === 1) {
+        entry.atlas.dispose();
+        charAtlasCache.splice(i, 1);
+      } else {
+        entry.ownedBy.splice(ownedByIndex, 1);
+      }
+      break;
+    }
+  }
+
+  // Try match a char atlas from the cache
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const entry = charAtlasCache[i];
+    if (configEquals(entry.config, newConfig)) {
+      // Add the renderer to the cache entry and return
+      entry.ownedBy.push(rendererId);
+      return entry.atlas;
+    }
+  }
+
+  const newEntry: ICharAtlasCacheEntry = {
+    atlas: new DynamicCharAtlas(
+      document,
+      newConfig
+    ),
+    config: newConfig,
+    ownedBy: [rendererId]
+  };
+  charAtlasCache.push(newEntry);
+  return newEntry.atlas;
+}
+
+/**
+ * Removes a terminal reference from the cache, allowing its memory to be freed.
+ */
+export function removeTerminalFromCache(rendererId: number): void {
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const index = charAtlasCache[i].ownedBy.indexOf(rendererId);
+    if (index !== -1) {
+      if (charAtlasCache[i].ownedBy.length === 1) {
+        // Remove the cache entry if it's the only renderer
+        charAtlasCache[i].atlas.dispose();
+        charAtlasCache.splice(i, 1);
+      } else {
+        // Remove the reference from the cache entry
+        charAtlasCache[i].ownedBy.splice(index, 1);
+      }
+      break;
+    }
+  }
+}