DartResolver.java

package com.jetbrains.lang.dart.resolve;

import com.intellij.openapi.project.Project;
import com.intellij.openapi.vfs.LocalFileSystem;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.PsiManager;
import com.intellij.psi.impl.source.resolve.ResolveCache;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.util.SmartList;
import com.jetbrains.lang.dart.analyzer.DartAnalysisServerService;
import com.jetbrains.lang.dart.analyzer.DartServerData;
import com.jetbrains.lang.dart.analyzer.DartServerData.DartNavigationRegion;
import com.jetbrains.lang.dart.analyzer.DartServerData.DartNavigationTarget;
import com.jetbrains.lang.dart.psi.*;
import com.jetbrains.lang.dart.util.DartResolveUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.List;

public class DartResolver implements ResolveCache.AbstractResolver<DartReference, List<? extends PsiElement>> {
  public static final DartResolver INSTANCE = new DartResolver();

  @Nullable
  @Override
  public List<? extends PsiElement> resolve(@NotNull DartReference reference, boolean incompleteCode) {
    reference = replaceQualifiedReferenceWithLast(reference);
    final PsiFile refPsiFile = reference.getContainingFile();
    int refOffset = reference.getTextRange().getStartOffset();
    int refLength = reference.getTextRange().getLength();
    DartNavigationRegion region = findRegion(refPsiFile, refOffset, refLength);

    if (region == null && reference instanceof DartLibraryId) {
      // DAS returns the whole "part of foo" as a region, but we have only "foo" as a reference
      final PsiElement parent = reference.getParent();
      if (parent instanceof DartPartOfStatement) {
        refOffset = parent.getTextRange().getStartOffset();
        refLength = reference.getTextRange().getEndOffset() - refOffset;
        region = findRegion(refPsiFile, refOffset, refLength);
      }
    }

    if (region == null && (reference instanceof DartSuperExpression || reference instanceof DartReferenceExpression)) {
      // DAS from SDK 1.13- returns 'super.foo' as a single range; SDK 1.14 returns 'super' and 'foo' separately.
      final PsiElement parent = reference.getParent();
      if (parent instanceof DartSuperCallOrFieldInitializer) {
        final List<DartExpression> expressions = ((DartSuperCallOrFieldInitializer)parent).getExpressionList();
        if (expressions.size() == 2 &&
            expressions.get(0) instanceof DartSuperExpression &&
            expressions.get(1) instanceof DartReferenceExpression) {
          refOffset = expressions.get(0).getTextRange().getStartOffset();
          refLength = expressions.get(1).getTextRange().getEndOffset() - refOffset;
          region = findRegion(refPsiFile, refOffset, refLength);
        }
      }
    }

    if (region != null) {
      final Project project = reference.getProject();
      final List<PsiElement> result = new SmartList<>();
      for (DartNavigationTarget target : region.getTargets()) {
        final PsiElement targetElement = getElementForNavigationTarget(project, target);
        if (targetElement != null) {
          result.add(targetElement);
        }
      }
      return result;
    }
    return null;
  }

  /**
   * When parameter information is requested for <code>items.insert(^)</code>,
   * we are given <code>items.insert</code>, but we cannot resolve it, we need just <code>insert</code>.
   */
  @NotNull
  private static DartReference replaceQualifiedReferenceWithLast(@NotNull DartReference reference) {
    final PsiElement lastChild = reference.getLastChild();
    if (lastChild instanceof DartReference) {
      reference = (DartReference)lastChild;
    }
    return reference;
  }

  @Nullable
  public static DartNavigationRegion findRegion(final PsiFile refPsiFile, final int refOffset, final int refLength) {
    final VirtualFile refVirtualFile = DartResolveUtil.getRealVirtualFile(refPsiFile);
    if (refVirtualFile != null) {
      final List<DartServerData.DartNavigationRegion> regions =
        DartAnalysisServerService.getInstance(refPsiFile.getProject()).getNavigation(refVirtualFile);
      return findRegion(regions, refOffset, refLength);
    }
    return null;
  }

  @Nullable
  public static PsiElement getElementForNavigationTarget(Project project, DartNavigationTarget target) {
    String targetPath = target.getFile();
    PsiFile file = findPsiFile(project, targetPath);
    if (file != null) {
      int targetOffset = target.getOffset(project, file.getVirtualFile());

      PsiElement elementAt = PsiTreeUtil.findElementOfClassAtOffset(file, targetOffset, DartComponentName.class, false);
      if (elementAt == null) elementAt = PsiTreeUtil.findElementOfClassAtOffset(file, targetOffset, DartLibraryNameElement.class, false);

      return elementAt;
    }

    return null;
  }

  @Nullable
  public static PsiFile findPsiFile(@NotNull Project project, @NotNull String path) {
    VirtualFile virtualFile = LocalFileSystem.getInstance().findFileByPath(path);
    if (virtualFile != null) {
      return PsiManager.getInstance(project).findFile(virtualFile);
    }
    return null;
  }

  /**
   * Find the region with the given offset in the given list of sorted regions.
   * Returns the found region or null.
   */
  @Nullable
  public static DartNavigationRegion findRegion(@NotNull final List<DartServerData.DartNavigationRegion> regions,
                                                final int offset,
                                                final int length) {
    int low = 0;
    int high = regions.size() - 1;

    while (low <= high) {
      int mid = (low + high) >>> 1;
      DartServerData.DartNavigationRegion midVal = regions.get(mid);
      int cmp = midVal.getOffset() - offset;

      if (cmp < 0) {
        low = mid + 1;
      }
      else if (cmp > 0) {
        high = mid - 1;
      }
      else {
        if (midVal.getLength() == length) {
          return midVal;
        }
        return null;
      }
    }
    return null;
  }
}