fs: extract binding error handling into a helper

PR-URL: #18642
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: joyeecheung

lib/fs.js

@@ -108,6 +108,20 @@ function copyObject(source) {
   return target;
 }
 
+function handleErrorFromBinding(ctx) {
+  if (ctx.errno !== undefined) {  // libuv error numbers
+    const err = errors.uvException(ctx);
+    Error.captureStackTrace(err, handleErrorFromBinding);
+    throw err;
+  } else if (ctx.error !== undefined) {  // errors created in C++ land.
+    // TODO(joyeecheung): currently, ctx.error are encoding errors
+    // usually caused by memory problems. We need to figure out proper error
+    // code(s) for this.
+    Error.captureStackTrace(ctx.error, handleErrorFromBinding);
+    throw ctx.error;
+  }
+}
+
 // TODO(joyeecheung): explore how the deprecation could be solved via linting
 // rules. See https://github.com/nodejs/node/pull/12976
 function rethrow() {
@@ -405,10 +419,7 @@ fs.accessSync = function(path, mode) {
 
   const ctx = { path };
   binding.access(pathModule.toNamespacedPath(path), mode, undefined, ctx);
-
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 // fs.exists never throws even when the arguments are invalid - if there is
@@ -742,9 +753,7 @@ fs.closeSync = function(fd) {
 
   const ctx = {};
   binding.close(fd, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 function modeNum(m, def) {
@@ -924,9 +933,7 @@ fs.renameSync = function(oldPath, newPath) {
   const ctx = { path: oldPath, dest: newPath };
   binding.rename(pathModule.toNamespacedPath(oldPath),
                  pathModule.toNamespacedPath(newPath), undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.truncate = function(path, len, callback) {
@@ -994,9 +1001,7 @@ fs.ftruncateSync = function(fd, len = 0) {
   len = Math.max(0, len);
   const ctx = {};
   binding.ftruncate(fd, len, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.rmdir = function(path, callback) {
@@ -1025,9 +1030,7 @@ fs.fdatasyncSync = function(fd) {
   validateUint32(fd, 'fd');
   const ctx = {};
   binding.fdatasync(fd, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.fsync = function(fd, callback) {
@@ -1041,9 +1044,7 @@ fs.fsyncSync = function(fd) {
   validateUint32(fd, 'fd');
   const ctx = {};
   binding.fsync(fd, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.mkdir = function(path, mode, callback) {
@@ -1114,9 +1115,7 @@ fs.fstatSync = function(fd) {
   validateUint32(fd, 'fd');
   const ctx = { fd };
   binding.fstat(fd, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
   return statsFromValues();
 };
 
@@ -1125,9 +1124,7 @@ fs.lstatSync = function(path) {
   validatePath(path);
   const ctx = { path };
   binding.lstat(pathModule.toNamespacedPath(path), undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
   return statsFromValues();
 };
 
@@ -1136,9 +1133,7 @@ fs.statSync = function(path) {
   validatePath(path);
   const ctx = { path };
   binding.stat(pathModule.toNamespacedPath(path), undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
   return statsFromValues();
 };
 
@@ -1159,14 +1154,7 @@ fs.readlinkSync = function(path, options) {
   const ctx = { path };
   const result = binding.readlink(pathModule.toNamespacedPath(path),
                                   options.encoding, undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  } else if (ctx.error) {
-    // TODO(joyeecheung): this is an encoding error usually caused by memory
-    // problems. We need to figure out proper error code(s) for this.
-    Error.captureStackTrace(ctx.error);
-    throw ctx.error;
-  }
+  handleErrorFromBinding(ctx);
   return result;
 };
 
@@ -1235,9 +1223,7 @@ fs.symlinkSync = function(target, path, type) {
   binding.symlink(preprocessSymlinkDestination(target, type, path),
                   pathModule.toNamespacedPath(path), flags, undefined, ctx);
 
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.link = function(existingPath, newPath, callback) {
@@ -1266,9 +1252,7 @@ fs.linkSync = function(existingPath, newPath) {
   const result = binding.link(pathModule.toNamespacedPath(existingPath),
                               pathModule.toNamespacedPath(newPath),
                               undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
   return result;
 };
 
@@ -1286,9 +1270,7 @@ fs.unlinkSync = function(path) {
   validatePath(path);
   const ctx = { path };
   binding.unlink(pathModule.toNamespacedPath(path), undefined, ctx);
-  if (ctx.errno !== undefined) {
-    throw errors.uvException(ctx);
-  }
+  handleErrorFromBinding(ctx);
 };
 
 fs.fchmod = function(fd, mode, callback) {
@@ -1887,9 +1869,7 @@ fs.realpathSync = function realpathSync(p, options) {
   if (isWindows && !knownHard[base]) {
     const ctx = { path: base };
     binding.lstat(pathModule.toNamespacedPath(base), undefined, ctx);
-    if (ctx.errno !== undefined) {
-      throw errors.uvException(ctx);
-    }
+    handleErrorFromBinding(ctx);
     knownHard[base] = true;
   }
 
@@ -1931,9 +1911,7 @@ fs.realpathSync = function realpathSync(p, options) {
       var baseLong = pathModule.toNamespacedPath(base);
       const ctx = { path: base };
       binding.lstat(baseLong, undefined, ctx);
-      if (ctx.errno !== undefined) {
-        throw errors.uvException(ctx);
-      }
+      handleErrorFromBinding(ctx);
 
       if ((statValues[1/*mode*/] & S_IFMT) !== S_IFLNK) {
         knownHard[base] = true;
@@ -1956,13 +1934,9 @@ fs.realpathSync = function realpathSync(p, options) {
       if (linkTarget === null) {
         const ctx = { path: base };
         binding.stat(baseLong, undefined, ctx);
-        if (ctx.errno !== undefined) {
-          throw errors.uvException(ctx);
-        }
+        handleErrorFromBinding(ctx);
         linkTarget = binding.readlink(baseLong, undefined, undefined, ctx);
-        if (ctx.errno !== undefined) {
-          throw errors.uvException(ctx);
-        }
+        handleErrorFromBinding(ctx);
       }
       resolvedLink = pathModule.resolve(previous, linkTarget);
 
@@ -1981,9 +1955,7 @@ fs.realpathSync = function realpathSync(p, options) {
     if (isWindows && !knownHard[base]) {
       const ctx = { path: base };
       binding.lstat(pathModule.toNamespacedPath(base), undefined, ctx);
-      if (ctx.errno !== undefined) {
-        throw errors.uvException(ctx);
-      }
+      handleErrorFromBinding(ctx);
       knownHard[base] = true;
     }
   }