TeaVmScriptLoader.java
package net.sourceforge.plantuml.teavm.browser;
import org.teavm.jso.JSBody;
import org.teavm.jso.JSFunctor;
import org.teavm.jso.JSObject;
public final class TeaVmScriptLoader {
// ::remove file when JAVA8
private static final Object LOCK = new Object();
private static volatile boolean loadSuccess;
private static volatile String loadError;
private static volatile boolean loadComplete;
@JSFunctor
public interface Ok extends JSObject {
void invoke();
}
@JSFunctor
public interface Err extends JSObject {
void invoke(String message);
}
/**
* Loads a JS file once. Multiple concurrent calls are coalesced. The state is
* stored on the global object.
* <p>
* Every lazily loaded support script comes through here: the stdlib bundles
* ({@code <lib>.min.js}) and also {@code themes.js}, {@code emoji.js} and
* {@code openiconic.js}, which all have the same problem this method's two
* host-provided globals solve. They are checked in this order:
* <ul>
* <li>{@code PLANTUML_STDLIB_LOADER}: a function {@code (url, onOk, onErr)}
* that delivers the script's content itself, in whatever way fits the host.
* For a stdlib bundle it populates {@code PLANTUML_STDLIB} /
* {@code PLANTUML_STDLIB_JSON} / {@code PLANTUML_STDLIB_INFO} for the
* library before calling {@code onOk}, or calls {@code onErr} with a
* message. Returning {@code false} (strictly) declines the URL, and loading
* proceeds through the script tag as if no hook were set, so a host that
* only handles stdlib bundles can decline {@code themes.js} and friends.
* The hook is the only way to load these files where a script tag cannot
* work: a Web Worker (no document), a browser extension that may fetch
* remote data but not execute remote code, or a non-browser runtime.
* Mirrors how a host can pre-populate {@code PLANTUML_THEMES} for
* {@link #getTheme(String)}.</li>
* <li>{@code PLANTUML_STDLIB_BASE}: a URL prefix for the script tag, so a
* page that imports the engine from a CDN can point the loading of all of
* these files at wherever they are hosted. Without it the URL stays
* relative, which resolves against the consuming document, not the
* engine's location.</li>
* </ul>
* A host may instead pre-populate the globals a script would have set and
* mark {@code __pl_script_state[url] = { state: 'loaded' }}; the fast path
* then skips loading entirely. With neither global set, the behaviour is
* exactly what it always was.
*/
@JSBody(params = { "url", "onOk", "onErr" }, script = "var w = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : window);"
+ "w.__pl_script_state = w.__pl_script_state || Object.create(null);" + "var st = w.__pl_script_state[url];"
+
"if (st && st.state === 'loaded') { onOk(); return; }"
+ "if (st && st.state === 'loading') { st.ok.push(onOk); st.err.push(onErr); return; }" +
"st = w.__pl_script_state[url] = { state: 'loading', ok: [onOk], err: [onErr] };" +
"var ok = function() {" + " st.state = 'loaded';" + " var list = st.ok; st.ok = []; st.err = [];"
+ " for (var i = 0; i < list.length; i++) list[i]();" + "};" +
"var fail = function(message) {" + " st.state = 'error';" + " var list = st.err; st.ok = []; st.err = [];"
+ " for (var i = 0; i < list.length; i++) list[i](message);" + "};" +
"if (typeof w.PLANTUML_STDLIB_LOADER === 'function') {"
+ " var handled = w.PLANTUML_STDLIB_LOADER(url, ok, function(message) { fail(message || ('Loader failed for ' + url)); });"
+ " if (handled !== false) return;" + "}" +
"var full = (typeof w.PLANTUML_STDLIB_BASE === 'string') ? (w.PLANTUML_STDLIB_BASE + url) : url;" +
"var s = document.createElement('script');" + "s.src = full;" + "s.async = true;" +
"s.onload = ok;" +
"s.onerror = function() { fail('Failed to load ' + full); };" +
"document.head.appendChild(s);")
public static native void loadOnce(String url, Ok onOk, Err onErr);
/**
* Retrieves the raw lines array for a .puml file from a loaded stdlib library.
*
* @param namespace the library name (e.g. "aws", "c4")
* @param path the relative path within the library (e.g. "compute/ec2")
* @return the JS array of lines, or null if not found
*/
@JSBody(params = { "namespace",
"path" }, script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "var ns = g.PLANTUML_STDLIB && g.PLANTUML_STDLIB[namespace];"
+ "return (ns && ns[path]) || null;")
public static native JSObject getRaw_PLANTUML_STDLIB(String namespace, String path);
/**
* Retrieves the raw text of a bundled theme, as published by themes.js into
* the PLANTUML_THEMES map.
* <p>
* Reads from the global object rather than from window, so that a host which
* pre-populates PLANTUML_THEMES (on globalThis) can use themes inside a Web
* Worker, where there is no document to append a script tag to, or in a
* non-browser JS runtime.
* @param name the theme name (e.g. "amiga")
* @return the whole .puml theme file as a string, or null if not present
*/
@JSBody(params = "name", script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "var t = g && g.PLANTUML_THEMES;" + "return (t && t[name]) ? t[name] : null;")
public static native String getTheme(String name);
/**
* Whether the PLANTUML_THEMES map exists at all, regardless of its content.
* <p>
* This is what distinguishes "themes.js was never loaded", which is a problem
* with the page's deployment, from "themes.js is loaded but has no theme of
* that name", which is a typo in the diagram text.
*/
@JSBody(params = {}, script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "return !!(g && g.PLANTUML_THEMES);")
public static native boolean hasThemes();
/**
* Writes a warning to the browser console, where the page author will see it.
*/
@JSBody(params = "message", script = "if (typeof console !== 'undefined' && console.warn) console.warn(message);")
public static native void consoleWarn(String message);
/**
*
* @param namespace
* @param path
* @return
*/
@JSBody(params = { "namespace",
"path" }, script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "var ns = g.PLANTUML_STDLIB_JSON && g.PLANTUML_STDLIB_JSON[namespace];"
+ "return (ns && ns[path]) || null;")
public static native JSObject getRaw_PLANTUML_STDLIB_JSON(String namespace, String path);
/**
* Retrieves the JSON info object for a loaded stdlib library.
* <p>
* This reads from {@code window.PLANTUML_STDLIB_INFO[namespace]}, which is
* populated by the generated JS files with metadata from each library's
* README.md YAML header (name, version, etc.).
*
* @param namespace the library name (e.g. "aws", "c4")
* @return the JS info object, or null if not found
*/
// Mirrors getRaw_PLANTUML_STDLIB but for the INFO metadata map
@JSBody(params = "namespace", script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "return (g.PLANTUML_STDLIB_INFO && g.PLANTUML_STDLIB_INFO[namespace]) || null;")
public static native JSObject getRaw_PLANTUML_STDLIB_INFO(String namespace);
/**
* Returns the keys of a JS object as a comma-separated string.
* <p>
* Useful for iterating over properties of a JSObject from Java side, since
* TeaVM does not allow direct enumeration of JS object keys.
*
* @param obj a JS object
* @return comma-separated keys, or empty string if null/empty
*/
@JSBody(params = "obj", script = "return obj ? Object.keys(obj).join(',') : '';")
public static native String getObjectKeys(JSObject obj);
/**
* Reads a single string property from a JS object by key.
*
* @param obj a JS object
* @param key the property name
* @return the property value as a string, or null
*/
@JSBody(params = { "obj", "key" }, script = "return (obj && obj[key] != null) ? String(obj[key]) : null;")
public static native String getStringProperty(JSObject obj, String key);
@JSBody(params = "lines", script = "return lines.join('\\n');")
public static native String joinLines(JSObject lines);
/**
* Serializes a JS object into a JSON string using the native
* {@code JSON.stringify}.
*
* @param obj a JS object
* @return the JSON string representation, or null if the object is null
*/
@JSBody(params = "obj", script = "return obj == null ? null : JSON.stringify(obj);")
public static native String stringify(JSObject obj);
@JSBody(params = "url", script = "var g = (typeof globalThis !== 'undefined') ? globalThis"
+ " : ((typeof self !== 'undefined') ? self : this);"
+ "var st = g.__pl_script_state && g.__pl_script_state[url];"
+ "return !!(st && st.state === 'loaded');")
private static native boolean isLoaded(String url);
/**
* Loads a script synchronously. Blocks until the script is loaded. MUST be
* called from a TeaVM thread context (not from native JS).
*/
public static void loadOnceSync(String url) {
// Fast path: already loaded
if (isLoaded(url))
return;
synchronized (LOCK) {
loadComplete = false;
loadSuccess = false;
loadError = null;
loadOnce(url, () -> {
synchronized (LOCK) {
loadSuccess = true;
loadComplete = true;
LOCK.notify();
}
}, (msg) -> {
synchronized (LOCK) {
loadSuccess = false;
loadError = msg;
loadComplete = true;
LOCK.notify();
}
});
while (!loadComplete) {
try {
LOCK.wait();
} catch (InterruptedException e) {
// retry
}
}
if (!loadSuccess)
throw new RuntimeException(loadError);
}
}
private TeaVmScriptLoader() {
}
}