Split file-based input errors into missing vs invalid #1542

docs/changelog.md

@@ -8,6 +8,9 @@ Requires libvips v8.7.0.
 
 * Input image decoding now fails fast, set `failOnError` to change this behaviour.
 
+* Failed filesystem-based input now separates missing file and invalid format errors.
+  [#1542](https://github.com/lovell/sharp/issues/1542)
+
 #### v0.21.2 - 13<sup>th</sup> January 2019
 
 * Ensure all metadata is removed from PNG output unless `withMetadata` used.

lib/output.js

@@ -32,7 +32,7 @@ const sharp = require('../build/Release/sharp.node');
  */
 function toFile (fileOut, callback) {
   if (!fileOut || fileOut.length === 0) {
-    const errOutputInvalid = new Error('Invalid output');
+    const errOutputInvalid = new Error('Missing output file path');
     if (is.fn(callback)) {
       callback(errOutputInvalid);
     } else {

src/common.cc

@@ -137,6 +137,7 @@ namespace sharp {
       case ImageType::VIPS: id = "v"; break;
       case ImageType::RAW: id = "raw"; break;
       case ImageType::UNKNOWN: id = "unknown"; break;
+      case ImageType::MISSING: id = "missing"; break;
     }
     return id;
   }
@@ -203,6 +204,10 @@ namespace sharp {
       } else if (EndsWith(loader, "Magick") || EndsWith(loader, "MagickFile")) {
         imageType = ImageType::MAGICK;
       }
+    } else {
+      if (EndsWith(vips::VError().what(), " not found\n")) {
+        imageType = ImageType::MISSING;
+      }
     }
     return imageType;
   }
@@ -269,6 +274,9 @@ namespace sharp {
       } else {
         // From filesystem
         imageType = DetermineImageType(descriptor->file.data());
+        if (imageType == ImageType::MISSING) {
+          throw vips::VError("Input file is missing");
+        }
         if (imageType != ImageType::UNKNOWN) {
           try {
             vips::VOption *option = VImage::option()
@@ -291,7 +299,7 @@ namespace sharp {
             throw vips::VError(std::string("Input file has corrupt header: ") + err.what());
           }
         } else {
-          throw vips::VError("Input file is missing or of an unsupported image format");
+          throw vips::VError("Input file contains unsupported image format");
         }
       }
     }

src/common.h

@@ -106,7 +106,8 @@ namespace sharp {
     FITS,
     VIPS,
     RAW,
-    UNKNOWN
+    UNKNOWN,
+    MISSING
   };
 
   // How many tasks are in the queue?

test/unit/io.js

@@ -263,7 +263,8 @@ describe('Input/output', function () {
 
   it('Fail when output File is input File', function (done) {
     sharp(fixtures.inputJpg).toFile(fixtures.inputJpg, function (err) {
-      assert(!!err);
+      assert(err instanceof Error);
+      assert.strictEqual('Cannot use same file for input and output', err.message);
       done();
     });
   });
@@ -273,14 +274,16 @@ describe('Input/output', function () {
       assert(false);
       done();
     }).catch(function (err) {
-      assert(!!err);
+      assert(err instanceof Error);
+      assert.strictEqual('Cannot use same file for input and output', err.message);
       done();
     });
   });
 
   it('Fail when output File is empty', function (done) {
     sharp(fixtures.inputJpg).toFile('', function (err) {
-      assert(!!err);
+      assert(err instanceof Error);
+      assert.strictEqual('Missing output file path', err.message);
       done();
     });
   });
@@ -290,7 +293,8 @@ describe('Input/output', function () {
       assert(false);
       done();
     }).catch(function (err) {
-      assert(!!err);
+      assert(err instanceof Error);
+      assert.strictEqual('Missing output file path', err.message);
       done();
     });
   });
@@ -301,6 +305,7 @@ describe('Input/output', function () {
       done();
     }).catch(function (err) {
       assert(err instanceof Error);
+      assert.strictEqual('Input buffer contains unsupported image format', err.message);
       done();
     });
   });
@@ -311,6 +316,18 @@ describe('Input/output', function () {
       done();
     }).catch(function (err) {
       assert(err instanceof Error);
+      assert.strictEqual('Input buffer contains unsupported image format', err.message);
+      done();
+    });
+  });
+
+  it('Fail when input file path is missing', function (done) {
+    sharp('does-not-exist').toBuffer().then(function () {
+      assert(false);
+      done();
+    }).catch(function (err) {
+      assert(err instanceof Error);
+      assert.strictEqual('Input file is missing', err.message);
       done();
     });
   });