1 files changed, 105 insertions, 0 deletions

diff --git a/vendor/github.com/hashicorp/terraform/plugin/discovery/requirements.go b/vendor/github.com/hashicorp/terraform/plugin/discovery/requirements.go
new file mode 100644
index 0000000..75430fd
--- /dev/null
+++ b/vendor/github.com/hashicorp/terraform/plugin/discovery/requirements.go
@@ -0,0 +1,105 @@
+package discovery
+
+import (
+        "bytes"
+)
+
+// PluginRequirements describes a set of plugins (assumed to be of a consistent
+// kind) that are required to exist and have versions within the given
+// corresponding sets.
+type PluginRequirements map[string]*PluginConstraints
+
+// PluginConstraints represents an element of PluginRequirements describing
+// the constraints for a single plugin.
+type PluginConstraints struct {
+        // Specifies that the plugin's version must be within the given
+        // constraints.
+        Versions Constraints
+
+        // If non-nil, the hash of the on-disk plugin executable must exactly
+        // match the SHA256 hash given here.
+        SHA256 []byte
+}
+
+// Allows returns true if the given version is within the receiver's version
+// constraints.
+func (s *PluginConstraints) Allows(v Version) bool {
+        return s.Versions.Allows(v)
+}
+
+// AcceptsSHA256 returns true if the given executable SHA256 hash is acceptable,
+// either because it matches the constraint or because there is no such
+// constraint.
+func (s *PluginConstraints) AcceptsSHA256(digest []byte) bool {
+        if s.SHA256 == nil {
+                return true
+        }
+        return bytes.Equal(s.SHA256, digest)
+}
+
+// Merge takes the contents of the receiver and the other given requirements
+// object and merges them together into a single requirements structure
+// that satisfies both sets of requirements.
+//
+// Note that it doesn't make sense to merge two PluginRequirements with
+// differing required plugin SHA256 hashes, since the result will never
+// match any plugin.
+func (r PluginRequirements) Merge(other PluginRequirements) PluginRequirements {
+        ret := make(PluginRequirements)
+        for n, c := range r {
+                ret[n] = &PluginConstraints{
+                        Versions: Constraints{}.Append(c.Versions),
+                        SHA256:   c.SHA256,
+                }
+        }
+        for n, c := range other {
+                if existing, exists := ret[n]; exists {
+                        ret[n].Versions = ret[n].Versions.Append(c.Versions)
+
+                        if existing.SHA256 != nil {
+                                if c.SHA256 != nil && !bytes.Equal(c.SHA256, existing.SHA256) {
+                                        // If we've been asked to merge two constraints with
+                                        // different SHA256 hashes then we'll produce a dummy value
+                                        // that can never match anything. This is a silly edge case
+                                        // that no reasonable caller should hit.
+                                        ret[n].SHA256 = []byte(invalidProviderHash)
+                                }
+                        } else {
+                                ret[n].SHA256 = c.SHA256 // might still be nil
+                        }
+                } else {
+                        ret[n] = &PluginConstraints{
+                                Versions: Constraints{}.Append(c.Versions),
+                                SHA256:   c.SHA256,
+                        }
+                }
+        }
+        return ret
+}
+
+// LockExecutables applies additional constraints to the receiver that
+// require plugin executables with specific SHA256 digests. This modifies
+// the receiver in-place, since it's intended to be applied after
+// version constraints have been resolved.
+//
+// The given map must include a key for every plugin that is already
+// required. If not, any missing keys will cause the corresponding plugin
+// to never match, though the direct caller doesn't necessarily need to
+// guarantee this as long as the downstream code _applying_ these constraints
+// is able to deal with the non-match in some way.
+func (r PluginRequirements) LockExecutables(sha256s map[string][]byte) {
+        for name, cons := range r {
+                digest := sha256s[name]
+
+                if digest == nil {
+                        // Prevent any match, which will then presumably cause the
+                        // downstream consumer of this requirements to report an error.
+                        cons.SHA256 = []byte(invalidProviderHash)
+                        continue
+                }
+
+                cons.SHA256 = digest
+        }
+}
+
+const invalidProviderHash = "<invalid>"