Fix Run.copyFile not to read an entire file into memory (#1041)

esy-build-package: fix Run.copyFile not to read entire file in memory

Also fix slowtest detection on azure.

Co-authored-by: Ulrik Strid <ulrik.strid@outlook.com>

esy-build-package/Run.re

@@ -129,8 +129,27 @@ let write = (~perm=?, ~data, path) =>
 let read = path => Bos.OS.File.read(path);
 
 let copyFile = (~perm=?, srcPath, dstPath) => {
-  let%bind data = read(srcPath);
-  write(~data, ~perm?, dstPath);
+  // Choosen "arbitrarily" but informed by:
+  // https://eklitzke.org/efficient-file-copying-on-linux
+  let buflen = 1024 * 128;
+  let buf = Bytes.create(buflen);
+  let rec loop = (ic, oc, ()) => {
+    switch (input(ic, buf, 0, buflen)) {
+    | 0 => return()
+    | n =>
+      output(oc, buf, 0, n);
+      loop(ic, oc, ());
+    };
+  };
+  let%bind res =
+    Bos.OS.File.with_ic(
+      srcPath,
+      (ic, ()) =>
+        Bos.OS.File.with_oc(~mode=?perm, dstPath, oc => loop(ic, oc), ()),
+      (),
+    );
+  let%bind res = res;
+  res;
 };
 
 let mv = Bos.OS.Path.move;

test-e2e-slow/run-slow-tests.js

@@ -5,7 +5,7 @@ const os = require('os');
 
 // this is required so esy won't "attach" to the outer esy project (esy
 // itself)
-delete process.env.ESY__ROOT_PACKAGE_CONFIG_PATH
+delete process.env.ESY__ROOT_PACKAGE_CONFIG_PATH;
 
 const isTaggedCommit = () => {
   const TRAVIS_TAG = process.env['TRAVIS_TAG'];
@@ -19,11 +19,14 @@ const isTaggedCommit = () => {
 const getCommitMessage = () => {
   const TRAVIS_COMMIT_MESSAGE = process.env['TRAVIS_COMMIT_MESSAGE'];
   const APPVEYOR_REPO_COMMIT_MESSAGE = process.env['APPVEYOR_REPO_COMMIT_MESSAGE'];
+  const AZURE_COMMIT_MESSAGE = process.env['Build.SourceVersionMessage'];
 
   if (TRAVIS_COMMIT_MESSAGE) {
     return TRAVIS_COMMIT_MESSAGE;
   } else if (APPVEYOR_REPO_COMMIT_MESSAGE) {
     return APPVEYOR_REPO_COMMIT_MESSAGE;
+  } else if (AZURE_COMMIT_MESSAGE) {
+    return AZURE_COMMIT_MESSAGE;
   } else {
     return execSync('git log -n1').toString('utf8');
   }
@@ -66,4 +69,3 @@ if (!isWindows) {
   require('./esy-npm-release/legacy.test.js');
 }
 require('./esy-npm-release/no-rewrite.test.js');
-