add release version check function

src/release.ts

@@ -0,0 +1,175 @@
+import * as core from '@actions/core';
+import * as httpm from '@actions/http-client';
+import * as semver from 'semver';
+
+export const storageUrl =
+  'https://storage.googleapis.com/flutter_infra/releases';
+
+interface IFlutterChannel {
+  [key: string]: string;
+  beta: string;
+  dev: string;
+  stable: string;
+}
+
+interface IFlutterRelease {
+  hash: string;
+  channel: string;
+  version: string;
+  archive: string;
+}
+
+interface IFlutterStorage {
+  current_release: IFlutterChannel;
+  releases: IFlutterRelease[];
+}
+
+export function getPlatform(): string {
+  const platform = process.platform;
+
+  if (platform == 'win32') {
+    return 'windows';
+  }
+
+  if (platform == 'darwin') {
+    return 'macos';
+  }
+
+  return platform;
+}
+
+export async function determineVersion(
+  version: string,
+  channel: string,
+  platform: string
+): Promise<{version: string; rawVersion: string; downloadUrl: string}> {
+  const storage = await getReleases(platform);
+
+  if (version === '') {
+    return getLatestVersion(storage, channel);
+  }
+
+  if (version.endsWith('.x')) {
+    return getWildcardVersion(storage, channel, version);
+  }
+
+  return getVersion(storage, channel, version);
+}
+
+async function getReleases(platform: string): Promise<IFlutterStorage> {
+  const releasesUrl: string = `${storageUrl}/releases_${platform}.json`;
+  const http: httpm.HttpClient = new httpm.HttpClient('flutter-action');
+  const storage: IFlutterStorage | null = (
+    await http.getJson<IFlutterStorage | null>(releasesUrl)
+  ).result;
+
+  if (!storage) {
+    throw new Error('unable to get flutter releases');
+  }
+
+  return storage;
+}
+
+async function getLatestVersion(
+  storage: IFlutterStorage,
+  channel: string
+): Promise<{version: string; rawVersion: string; downloadUrl: string}> {
+  const channelVersion = storage.releases.find(release => {
+    return (
+      release.hash === storage.current_release[channel] &&
+      release.channel == channel
+    );
+  });
+
+  if (!channelVersion) {
+    throw new Error(`unable to get latest version from channel ${channel}`);
+  }
+
+  let rver = channelVersion.version;
+  let cver = rver.startsWith('v') ? rver.slice(1, rver.length) : rver;
+
+  core.debug(`latest version from channel ${channel} is ${rver}`);
+
+  return {
+    version: cver,
+    rawVersion: rver,
+    downloadUrl: `${storageUrl}/${channelVersion.archive}`
+  };
+}
+
+async function getWildcardVersion(
+  storage: IFlutterStorage,
+  channel: string,
+  version: string
+): Promise<{version: string; rawVersion: string; downloadUrl: string}> {
+  let sver = version.endsWith('.x')
+    ? version.slice(0, version.length - 2)
+    : version;
+
+  const releases = storage.releases.filter(release => {
+    if (release.channel != channel) return false;
+    return prefixCompare(sver, release.version);
+  });
+
+  const versions = releases
+    .map(release => release.version)
+    .map(version =>
+      version.startsWith('v') ? version.slice(1, version.length) : version
+    );
+
+  const sortedVersions = versions.sort(semver.rcompare);
+
+  let cver = sortedVersions[0];
+  let release = releases.find(release => compare(cver, release.version));
+
+  if (!release) {
+    throw new Error(`unable to find release for ${version}`);
+  }
+
+  core.debug(
+    `latest version of ${version} from channel ${channel} is ${release.version}`
+  );
+
+  return {
+    version: cver,
+    rawVersion: release.version,
+    downloadUrl: `${storageUrl}/${release.archive}`
+  };
+}
+
+async function getVersion(
+  storage: IFlutterStorage,
+  channel: string,
+  version: string
+): Promise<{version: string; rawVersion: string; downloadUrl: string}> {
+  const release = storage.releases.find(release => {
+    if (release.channel != channel) return false;
+    return compare(version, release.version);
+  });
+
+  if (!release) {
+    return getWildcardVersion(storage, channel, version);
+  }
+
+  return {
+    version,
+    rawVersion: release.version,
+    downloadUrl: `${storageUrl}/${release.archive}`
+  };
+}
+
+function compare(version: string, releaseVersion: string): boolean {
+  if (releaseVersion.startsWith('v')) {
+    return releaseVersion === `v${version}`;
+  }
+
+  return releaseVersion === version;
+}
+
+function prefixCompare(version: string, releaseVersion: string): boolean {
+  if (releaseVersion.startsWith('v')) {
+    return releaseVersion.startsWith(`v${version}`);
+  }
+
+  return releaseVersion.startsWith(version);
+}