9 files changed, 198 insertions, 0 deletions
diff --git a/packages/resolver/src/index.ts b/packages/resolver/src/index.ts
new file mode 100644
index 000000000..cd6ec42ec
--- /dev/null
+++ b/packages/resolver/src/index.ts
@@ -0,0 +1,8 @@
+export { ContractSource, ContractSources } from './types';
+export { FallthroughResolver } from './resolvers/fallthrough_resolver';
+export { URLResolver } from './resolvers/url_resolver';
+export { NPMResolver } from './resolvers/npm_resolver';
+export { FSResolver } from './resolvers/fs_resolver';
+export { NameResolver } from './resolvers/name_resolver';
+export { EnumerableResolver } from './resolvers/enumerable_resolver';
+export { Resolver } from './resolvers/resolver';
diff --git a/packages/resolver/src/resolvers/enumerable_resolver.ts b/packages/resolver/src/resolvers/enumerable_resolver.ts
new file mode 100644
index 000000000..bb578bb86
--- /dev/null
+++ b/packages/resolver/src/resolvers/enumerable_resolver.ts
@@ -0,0 +1,7 @@
+import { ContractSource } from '../types';
+
+import { Resolver } from './resolver';
+
+export abstract class EnumerableResolver extends Resolver {
+    public abstract getAllContracts(): ContractSource[];
+}
diff --git a/packages/resolver/src/resolvers/fallthrough_resolver.ts b/packages/resolver/src/resolvers/fallthrough_resolver.ts
new file mode 100644
index 000000000..8f6af9be0
--- /dev/null
+++ b/packages/resolver/src/resolvers/fallthrough_resolver.ts
@@ -0,0 +1,21 @@
+import * as _ from 'lodash';
+
+import { ContractSource } from '../types';
+
+import { Resolver } from './resolver';
+
+export class FallthroughResolver extends Resolver {
+    private _resolvers: Resolver[] = [];
+    public appendResolver(resolver: Resolver): void {
+        this._resolvers.push(resolver);
+    }
+    public resolveIfExists(importPath: string): ContractSource | undefined {
+        for (const resolver of this._resolvers) {
+            const contractSourceIfExists = resolver.resolveIfExists(importPath);
+            if (!_.isUndefined(contractSourceIfExists)) {
+                return contractSourceIfExists;
+            }
+        }
+        return undefined;
+    }
+}
diff --git a/packages/resolver/src/resolvers/fs_resolver.ts b/packages/resolver/src/resolvers/fs_resolver.ts
new file mode 100644
index 000000000..4f05fba88
--- /dev/null
+++ b/packages/resolver/src/resolvers/fs_resolver.ts
@@ -0,0 +1,19 @@
+import * as fs from 'fs';
+
+import { ContractSource } from '../types';
+
+import { Resolver } from './resolver';
+
+export class FSResolver extends Resolver {
+    // tslint:disable-next-line:prefer-function-over-method
+    public resolveIfExists(importPath: string): ContractSource | undefined {
+        if (fs.existsSync(importPath)) {
+            const fileContent = fs.readFileSync(importPath).toString();
+            return {
+                source: fileContent,
+                path: importPath,
+            };
+        }
+        return undefined;
+    }
+}
diff --git a/packages/resolver/src/resolvers/name_resolver.ts b/packages/resolver/src/resolvers/name_resolver.ts
new file mode 100644
index 000000000..522e10142
--- /dev/null
+++ b/packages/resolver/src/resolvers/name_resolver.ts
@@ -0,0 +1,66 @@
+import * as fs from 'fs';
+import * as _ from 'lodash';
+import * as path from 'path';
+
+import { ContractSource } from '../types';
+
+import { EnumerableResolver } from './enumerable_resolver';
+
+export class NameResolver extends EnumerableResolver {
+    private _contractsDir: string;
+    constructor(contractsDir: string) {
+        super();
+        this._contractsDir = contractsDir;
+    }
+    public resolveIfExists(lookupContractName: string): ContractSource | undefined {
+        const SOLIDITY_FILE_EXTENSION = '.sol';
+        let contractSource: ContractSource | undefined;
+        const onFile = (filePath: string) => {
+            const contractName = path.basename(filePath, SOLIDITY_FILE_EXTENSION);
+            if (contractName === lookupContractName) {
+                const source = fs.readFileSync(filePath).toString();
+                contractSource = {
+                    source,
+                    path: filePath,
+                };
+                return true;
+            }
+            return undefined;
+        };
+        this._traverseContractsDir(this._contractsDir, onFile);
+        return contractSource;
+    }
+    public getAllContracts(): ContractSource[] {
+        const SOLIDITY_FILE_EXTENSION = '.sol';
+        const contractSources: ContractSource[] = [];
+        const onFile = (filePath: string) => {
+            const contractName = path.basename(filePath, SOLIDITY_FILE_EXTENSION);
+            const source = fs.readFileSync(filePath).toString();
+            const contractSource = {
+                source,
+                path: filePath,
+            };
+            contractSources.push(contractSource);
+        };
+        this._traverseContractsDir(this._contractsDir, onFile);
+        return contractSources;
+    }
+    // tslint:disable-next-line:prefer-function-over-method
+    private _traverseContractsDir(dirPath: string, onFile: (filePath: string) => true | void): boolean {
+        let dirContents: string[] = [];
+        try {
+            dirContents = fs.readdirSync(dirPath);
+        } catch (err) {
+            throw new Error(`No directory found at ${dirPath}`);
+        }
+        for (const fileName of dirContents) {
+            const entryPath = path.join(dirPath, fileName);
+            const isDirectory = fs.lstatSync(entryPath).isDirectory();
+            const isComplete = isDirectory ? this._traverseContractsDir(entryPath, onFile) : onFile(entryPath);
+            if (isComplete) {
+                return isComplete;
+            }
+        }
+        return false;
+    }
+}
diff --git a/packages/resolver/src/resolvers/npm_resolver.ts b/packages/resolver/src/resolvers/npm_resolver.ts
new file mode 100644
index 000000000..2c0a44aad
--- /dev/null
+++ b/packages/resolver/src/resolvers/npm_resolver.ts
@@ -0,0 +1,34 @@
+import * as fs from 'fs';
+import * as path from 'path';
+
+import { ContractSource } from '../types';
+
+import { Resolver } from './resolver';
+
+export class NPMResolver extends Resolver {
+    private _packagePath: string;
+    constructor(packagePath: string) {
+        super();
+        this._packagePath = packagePath;
+    }
+    public resolveIfExists(importPath: string): ContractSource | undefined {
+        if (!importPath.startsWith('/')) {
+            const [packageName, ...other] = importPath.split('/');
+            const pathWithinPackage = path.join(...other);
+            let currentPath = this._packagePath;
+            const ROOT_PATH = '/';
+            while (currentPath !== ROOT_PATH) {
+                const lookupPath = path.join(currentPath, 'node_modules', packageName, pathWithinPackage);
+                if (fs.existsSync(lookupPath)) {
+                    const fileContent = fs.readFileSync(lookupPath).toString();
+                    return {
+                        source: fileContent,
+                        path: lookupPath,
+                    };
+                }
+                currentPath = path.dirname(currentPath);
+            }
+        }
+        return undefined;
+    }
+}
diff --git a/packages/resolver/src/resolvers/resolver.ts b/packages/resolver/src/resolvers/resolver.ts
new file mode 100644
index 000000000..7edc9a85d
--- /dev/null
+++ b/packages/resolver/src/resolvers/resolver.ts
@@ -0,0 +1,14 @@
+import * as _ from 'lodash';
+
+import { ContractSource } from '../types';
+
+export abstract class Resolver {
+    public abstract resolveIfExists(importPath: string): ContractSource | undefined;
+    public resolve(importPath: string): ContractSource {
+        const contractSourceIfExists = this.resolveIfExists(importPath);
+        if (_.isUndefined(contractSourceIfExists)) {
+            throw new Error(`Failed to resolve ${importPath}`);
+        }
+        return contractSourceIfExists;
+    }
+}
diff --git a/packages/resolver/src/resolvers/url_resolver.ts b/packages/resolver/src/resolvers/url_resolver.ts
new file mode 100644
index 000000000..180b0c9f6
--- /dev/null
+++ b/packages/resolver/src/resolvers/url_resolver.ts
@@ -0,0 +1,21 @@
+import * as fs from 'fs';
+
+import { ContractSource } from '../types';
+
+import { Resolver } from './resolver';
+
+export class URLResolver extends Resolver {
+    // tslint:disable-next-line:prefer-function-over-method
+    public resolveIfExists(importPath: string): ContractSource | undefined {
+        const FILE_URL_PREXIF = 'file://';
+        if (importPath.startsWith(FILE_URL_PREXIF)) {
+            const filePath = importPath.substr(FILE_URL_PREXIF.length);
+            const fileContent = fs.readFileSync(filePath).toString();
+            return {
+                source: fileContent,
+                path: importPath,
+            };
+        }
+        return undefined;
+    }
+}
diff --git a/packages/resolver/src/types.ts b/packages/resolver/src/types.ts
new file mode 100644
index 000000000..41492622d
--- /dev/null
+++ b/packages/resolver/src/types.ts
@@ -0,0 +1,8 @@
+export interface ContractSource {
+    source: string;
+    path: string;
+}
+
+export interface ContractSources {
+    [key: string]: ContractSource;
+}