com.facebook.buck.core.rules.impl

Class NoopBuildRule

java.lang.Object

com.facebook.buck.core.rules.impl.AbstractBuildRule

com.facebook.buck.core.rules.impl.NoopBuildRule

All Implemented Interfaces:

BuildEngineAction, AllowsNonAnnotatedFields, SupportsInputBasedRuleKey, BuildRule, HasNameAndType, Comparable<BuildRule>

Direct Known Subclasses:

AppleToolchainBuildRule, AppleToolchainSetBuildRule, CommandAlias, ExternalTestRunner, GoTestRunner, NdkToolchainBuildRule, PythonTestRunner, SwiftToolchainBuildRule

public class NoopBuildRule
extends AbstractBuildRule
implements SupportsInputBasedRuleKey

A BuildRule which has no output. This is used in the following ways:

1. When a target has multiple potential outputs (e.g. a CxxLibrary may be static or shared). Flavored versions of the target will actually do work (and be depended on) in the action graph. However, the target graph to action graph conversion assumes that every node in the target graph will have a corresponding node in the action graph, so we create a NoopBuildRuleWithDeclaredAndExtraDeps to keep to that constraint, even though the actual work is done by the flavored versions.
2. When a target has no output artifacts, but its exit code may be interesting. e.g. TestRules may not have any build steps to perform, but have runTests Steps to run to determine their exit code.
3. When a target just forwards an existing file, e.g. for prebuilt library rules, or if all the work is actually done on a depending rule (e.g. Lua).

Constructor Summary

Constructors

Constructor and Description
NoopBuildRule(BuildTarget buildTarget, ProjectFilesystem projectFilesystem)

Method Summary

Modifier and Type	Method and Description
SortedSet<BuildRule>	getBuildDeps()
com.google.common.collect.ImmutableList<Step>	getBuildSteps(BuildContext context, BuildableContext buildableContext)
SourcePath	getSourcePathToOutput()
boolean	hasBuildSteps() Whether this BuildRule may have any steps to build.
boolean	isCacheable() Whether this BuildRule can be cached.

Methods inherited from class com.facebook.buck.core.rules.impl.AbstractBuildRule

equals, getBuildTarget, getDependencies, getProjectFilesystem, getSourcePathOutputs, getType, hashCode, injectFields, toString, updateBuildRuleResolver

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.facebook.buck.core.rules.attr.SupportsInputBasedRuleKey

inputBasedRuleKeyIsEnabled, isSupported

Methods inherited from interface com.facebook.buck.core.rules.BuildRule

compareTo, getBuildTarget, getFullyQualifiedName, getProjectFilesystem, outputFileCanBeCopied, shouldRespectInputSizeLimitForRemoteExecution, toString, updateBuildRuleResolver

Methods inherited from interface com.facebook.buck.core.build.action.BuildEngineAction

getDependencies, getSourcePathOutputs

Methods inherited from interface com.facebook.buck.core.rules.HasNameAndType

getType

Constructor Detail

NoopBuildRule

public NoopBuildRule(BuildTarget buildTarget,
                     ProjectFilesystem projectFilesystem)

Method Detail

getBuildDeps

public final SortedSet<BuildRule> getBuildDeps()

Specified by:

getBuildDeps in interface BuildRule

Returns:

the set of rules that must be built before this rule. Normally, this matches the value of the deps argument for this build rule in the build file in which it was defined.

However, there are special cases where other arguments pull in implicit dependencies (e.g., the keystore argument in android_binary). In these cases, the implicit dependencies are also included in the set returned by this method. The value of the original deps argument, as defined in the build file, must be accessed via a custom getter provided by the build rule.

getBuildSteps

public final com.google.common.collect.ImmutableList<Step> getBuildSteps(BuildContext context,
                                                                         BuildableContext buildableContext)

Specified by:

getBuildSteps in interface BuildRule

hasBuildSteps

public final boolean hasBuildSteps()

Description copied from interface: BuildRule

Whether this BuildRule may have any steps to build.

Specified by:

hasBuildSteps in interface BuildRule

Overrides:

hasBuildSteps in class AbstractBuildRule

getSourcePathToOutput

@Nullable
public final SourcePath getSourcePathToOutput()

Specified by:

getSourcePathToOutput in interface BuildRule

isCacheable

public final boolean isCacheable()

Description copied from interface: BuildRule

Whether this BuildRule can be cached.

Uncached build rules are never written out to cache, never read from cache, and does not count in cache statistics. This rule is useful for artifacts which cannot be easily normalized.

Uncached rules are not always rebuilt, however, as long as the existing on-disk representation is up to date. This means that these rules can take advantage of SupportsInputBasedRuleKey to prevent rebuilding.

Specified by:

isCacheable in interface BuildEngineAction

Specified by:

isCacheable in interface BuildRule

Overrides:

isCacheable in class AbstractBuildRule