FieldValueMigration.h header
#include <ew/app/FieldValueMigration.h>Namespace ew::app
FieldValueMigrationProblem struct
struct ew::app::FieldValueMigrationProblemOne value the migration could not turn into the type its field declares.
Reported, never dropped. A migration that quietly discarded "about forty" from a Number field would destroy the only record that anybody had written it, and would do so in the one operation a writer has no reason to watch. The value stays exactly as it was, as Text, and appears here.
Members
ew::core::foundation::ContentId ew::app::entity::FieldValueMigrationProblem::entityIdThe entity holding it.
QString ew::app::entity::FieldValueMigrationProblem::entityNameWhat the entity is called, so the report reads as a place rather than an id.
QString ew::app::entity::FieldValueMigrationProblem::keyThe field key.
QString ew::app::entity::FieldValueMigrationProblem::textThe text that would not convert, verbatim.
QString ew::app::entity::FieldValueMigrationProblem::messageOne sentence naming what is wrong with it.
bool operator==(const FieldValueMigrationProblem &, const FieldValueMigrationProblem &)=defaultProblems compare equal when every field matches.
FieldValueMigrationReport struct
struct ew::app::FieldValueMigrationReportWhat a migration did, and what it could not do.
Members
int ew::app::entity::FieldValueMigrationReport::converted = 0How many values were converted from text to their declared type.
int ew::app::entity::FieldValueMigrationReport::alreadyTyped = 0How many were already of the right type, or were text fields needing no conversion.
std::vector<FieldValueMigrationProblem> ew::app::entity::FieldValueMigrationReport::problemsEvery value that would not convert. See FieldValueMigrationProblem.
bool ew::app::entity::FieldValueMigrationReport::isEmpty() constWhether anything at all needs doing.
Functions
QString ew::app::entity::describeFieldValueMigration(const FieldValueMigrationReport &report)report written for a person to read, as Markdown.
The problems come first and are named individually. A count alone would tell a writer that something was left behind without telling them where to look, which is the same as not telling them.
std::unique_ptr< ew::core::undo::Command > ew::app::entity::makeFieldValueMigrationCommand(ew::core::project::Project &project)The command that performs the migration described by planFieldValueMigration.
Undoable like any other edit – which matters more here than almost anywhere, because it touches every entity in the project at once and a writer who dislikes the result must be able to say so. Values that will not convert are left exactly as they are.
Returns null when there is nothing to convert, so a caller can tell "already done" from "done".
FieldValueMigrationReport ew::app::entity::planFieldValueMigration(const ew::core::project::Project &project)What migrating project would do, without doing it.
Every value stored as Text whose field declares another type is a candidate: projects written before values were typed hold all of them that way. A value already of its declared type is left alone and counted, so running this twice is safe and the second run reports nothing to do.