/// <summary>
/// Generate a list of artifact summary information from a resource input stream,
/// using the default <see cref="ConformanceHarvesters"/>.
/// <para>
/// If the target resource represents a <see cref="Bundle"/> instance, then the generator
/// returns a list of summaries for all resource entries contained in the bundle.
/// </para>
/// </summary>
/// <param name="navStream">An <see cref="INavigatorStream"/> instance.</param>
/// <param name="initProperties">
/// An optional summary properties initialization method, or <c>null</c>.
/// If specified, the generator will call this method for each generated summary,
/// allowing the caller to modify or enrich the set of generated summary properties.
/// </param>
/// <param name="harvesters">
/// A list of <see cref="ArtifactSummaryHarvester"/> delegates that the
/// generator calls to harvest summary information from each artifact.
/// If the harvester list equals <c>null</c> or empty, then the generator will
/// harvest only the common default summary properties.
/// </param>
/// <returns>A list of new <see cref="ArtifactSummary"/> instances.</returns>
/// <remarks>
/// The generator catches all runtime exceptions that occur during harvesting and returns
/// them as <see cref="ArtifactSummary"/> instances with <see cref="ArtifactSummary.IsFaulted"/>
/// equal to <c>true</c> and <see cref="ArtifactSummary.Error"/> returning the exception.
/// </remarks>
public static List <ArtifactSummary> Generate(
INavigatorStream navStream,
Action <ArtifactSummaryPropertyBag> initProperties,
params ArtifactSummaryHarvester[] harvesters)
{
var result = new List <ArtifactSummary>();
// Factory returns null for unknown file formats
if (navStream == null)
{
return(result);
}
try
{
// Run default or specified (custom) harvesters
if (harvesters == null || harvesters.Length == 0)
{
harvesters = ConformanceHarvesters;
}
while (navStream.MoveNext())
{
var current = navStream.Current;
if (current != null)
{
var properties = new ArtifactSummaryPropertyBag();
// Initialize default summary information
// Note: not exposed by IElementNavigator, cannot use harvester
properties.SetPosition(navStream.Position);
properties.SetTypeName(current.Type);
properties.SetResourceUri(navStream.Position);
// Allow caller to modify/enrich harvested properties
initProperties?.Invoke(properties);
// Generate the final (immutable) ArtifactSummary instance
var summary = generate(properties, current, harvesters);
result.Add(summary);
}
}
}
// TODO Catch specific exceptions
// catch (System.IO.FileNotFoundException)
// catch (UnauthorizedAccessException)
// catch (System.Security.SecurityException)
// catch (FormatException)
catch (Exception ex)
{
result.Add(ArtifactSummary.FromException(ex));
}
finally
{
navStream?.Dispose();
}
return(result);
}
/// <summary>Generate a list of artifact summary information from an <see cref="INavigatorStream"/> instance.</summary>
/// <param name="origin">The original location of the target artifact (or the containing Bundle).</param>
/// <param name="harvesters">
/// An optional list of <see cref="ArtifactSummaryHarvester"/> delegates that the generator will call
/// instead of the default harvesters to harvest summary information from an artifact.
/// </param>
/// <returns>A list of new <see cref="ArtifactSummary"/> instances.</returns>
/// <remarks>
/// For each artifact, the generator executes all (default or specified) harvester delegates
/// in the specified order. When a delegate returns <c>true</c> to signal that harvesting has
/// finished, the generator will not call any of the remaining delegates and immediately
/// proceed to create the final <see cref="ArtifactSummary"/> return value.
/// <para>
/// By default, if the <paramref name="harvesters"/> parameter value is null or empty, the
/// <see cref="ArtifactSummaryGenerator"/> calls the built-in default harvesters
/// as specified by <see cref="ArtifactSummaryGenerator.DefaultHarvesters"/>.
/// However if the caller specifies one or more harvester delegates, then the summary
/// generator calls only the provided delegates, in the specified order.
/// A custom delegate array may include one or more of the default harvesters.
/// </para>
/// <para>
/// The generator catches all runtime exceptions that occur during harvesting and returns
/// them as <see cref="ArtifactSummary"/> instances with <see cref="ArtifactSummary.IsFaulted"/>
/// equal to <c>true</c> and <see cref="ArtifactSummary.Error"/> returning the exception.
/// </para>
/// </remarks>
public static List <ArtifactSummary> Generate(
string origin,
params ArtifactSummaryHarvester[] harvesters)
{
var result = new List <ArtifactSummary>();
// In case of error, return completed summaries and error info
INavigatorStream navStream = null;
try
{
// Call default navigator factory
navStream = DefaultNavigatorStreamFactory.Create(origin);
// Get some source file properties
var fi = new FileInfo(origin);
// Factory returns null for unknown file formats
if (navStream == null)
{
return(result);
}
// Run default or specified (custom) harvesters
if (harvesters == null || harvesters.Length == 0)
{
harvesters = DefaultHarvesters;
}
while (navStream.MoveNext())
{
var current = navStream.Current;
if (current != null)
{
var properties = new ArtifactSummaryPropertyBag();
// Initialize default summary information
// Note: not exposed by IElementNavigator, cannot use harvester
properties.SetOrigin(origin);
properties.SetFileSize(fi.Length);
properties.SetLastModified(fi.LastWriteTimeUtc);
properties.SetPosition(navStream.Position);
properties.SetTypeName(current.Type);
properties.SetResourceUri(navStream.Position);
var summary = generate(properties, current, harvesters);
result.Add(summary);
}
}
}
// TODO Catch specific exceptions
// catch (System.IO.FileNotFoundException)
// catch (UnauthorizedAccessException)
// catch (System.Security.SecurityException)
// catch (FormatException)
catch (Exception ex)
{
result.Add(ArtifactSummary.FromException(ex, origin));
}
finally
{
navStream?.Dispose();
}
return(result);
}