Move remaining webgl atlas to shared

src/browser/renderer/shared/CharAtlasCache.ts

@@ -0,0 +1,97 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { TextureAtlas } from 'browser/renderer/shared/TextureAtlas';
+import { Terminal } from 'xterm';
+import { IColorSet, ITerminal } from 'browser/Types';
+import { ICharAtlasConfig, ITextureAtlas } from 'browser/renderer/shared/Types';
+import { generateConfig, configEquals } from 'browser/renderer/shared/CharAtlasUtils';
+
+interface ITextureAtlasCacheEntry {
+  atlas: ITextureAtlas;
+  config: ICharAtlasConfig;
+  // N.B. This implementation potentially holds onto copies of the terminal forever, so
+  // this may cause memory leaks.
+  ownedBy: Terminal[];
+}
+
+const charAtlasCache: ITextureAtlasCacheEntry[] = [];
+
+/**
+ * Acquires a char atlas, either generating a new one or returning an existing
+ * one that is in use by another terminal.
+ * @param terminal The terminal.
+ * @param colors The colors to use.
+ */
+export function acquireTextureAtlas(
+  terminal: Terminal,
+  colors: IColorSet,
+  scaledCellWidth: number,
+  scaledCellHeight: number,
+  scaledCharWidth: number,
+  scaledCharHeight: number,
+  devicePixelRatio: number
+): ITextureAtlas {
+  const newConfig = generateConfig(scaledCellWidth, scaledCellHeight, scaledCharWidth, scaledCharHeight, terminal, colors, devicePixelRatio);
+
+  // Check to see if the terminal already owns this config
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const entry = charAtlasCache[i];
+    const ownedByIndex = entry.ownedBy.indexOf(terminal);
+    if (ownedByIndex >= 0) {
+      if (configEquals(entry.config, newConfig)) {
+        return entry.atlas;
+      }
+      // The configs differ, release the terminal 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 terminal to the cache entry and return
+      entry.ownedBy.push(terminal);
+      return entry.atlas;
+    }
+  }
+
+  const core: ITerminal = (terminal as any)._core;
+  const newEntry: ITextureAtlasCacheEntry = {
+    atlas: new TextureAtlas(document, newConfig, core.unicodeService),
+    config: newConfig,
+    ownedBy: [terminal]
+  };
+  charAtlasCache.push(newEntry);
+  return newEntry.atlas;
+}
+
+/**
+ * Removes a terminal reference from the cache, allowing its memory to be freed.
+ * @param terminal The terminal to remove.
+ */
+export function removeTerminalFromCache(terminal: Terminal): void {
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const index = charAtlasCache[i].ownedBy.indexOf(terminal);
+    if (index !== -1) {
+      if (charAtlasCache[i].ownedBy.length === 1) {
+        // Remove the cache entry if it's the only terminal
+        charAtlasCache[i].atlas.dispose();
+        charAtlasCache.splice(i, 1);
+      } else {
+        // Remove the reference from the cache entry
+        charAtlasCache[i].ownedBy.splice(index, 1);
+      }
+      break;
+    }
+  }
+}